# Problem about POST https://api.eu.nylas.com/v3/connect/token request **URL:** \ **Category:** Question and Answers\ **Tags:** authentication\ **Created:** [July 24, 2024, 1:49pm UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291 "2024-07-24T13:49:25Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![efeengin](https://avatars.discourse-cdn.com/v4/letter/e/3e96dc/32.png) [@efeengin](https://forums.nylas.com/u/efeengin)\ **Post date:** [July 24, 2024, 1:49pm UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/1 "2024-07-24T13:49:26Z")
Hello everyone. I am using v3 api and getting **code** from previous Oauth Request. then I am making connect/token request to get grant\_id to save. I am always getting **“error\_code”:45004,“error\_description”:“Code verifier challenge failed”** I create code verifier than making a challenge from it . method is either plain or s256 it fails. I thought I am making a mistake when creating PKCE I used another library to validate my own verifier and challenge [https://github.com/AdrienGras/pkce-php](https://github.com/AdrienGras/pkce-php) it validates. any ideas what to do ? thanks for help in advance. ---
**Author:** ![ram](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.nylas.com/ram/32/3_2.png) [@ram](https://forums.nylas.com/u/ram)\ **Post date:** [July 24, 2024, 2:31pm UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/2 "2024-07-24T14:31:22Z")
@efeengin just wondering what platform did you specify for hosted authenciation? ![Screenshot 2024-07-24 at 10.30.51 AM](https://us1.discourse-cdn.com/flex015/uploads/nylas3/original/1X/9fec479aa30aff1424d341b228ec3642243ae7cc.png) For frontend authentication, it should be `JavaScript` Also I created a reference code sample for PKCE using `nylas-identity`: [GitHub - nylas-samples/nylas-auth-flow-react-spa: Authentication Users Accounts in a Single Page Application / Mobile App](https://github.com/nylas-samples/nylas-auth-flow-react-spa) ---
**Author:** ![efeengin](https://avatars.discourse-cdn.com/v4/letter/e/3e96dc/32.png) [@efeengin](https://forums.nylas.com/u/efeengin)\ **Post date:** [July 24, 2024, 3:30pm UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/3 "2024-07-24T15:30:57Z")
@ram it is website . to /auth endpoint I am making this request ```auto client_id=exxxxxa&access_type=offline&login_hint=efexxxxxxx35%40gmail.com&prompt=select_provider&response_type=code&redirect_uri=http%3A%2F%2Flocalhost%2Fintegrations%2Fnylasv3-callback&code_challenge=ZTk2YmY2Njg2YTNjMzUxMGU5ZTkyN2RiNzA2OWNiMWNiYTliOTliMDIyZjQ5NDgzYTZjZTMyNzA4MDllNjhhMg&code_challenge_method=S256 ``` then I am trying to get grant from /token endpoint with this request ```auto array:6 [▼ "client_id" => "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" "client_secret" => "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" "grant_type" => "authorization_code" "code" => "09w1xSghI6798E_0zXnIh1mBnsQYHvpqc7Btez3wCyLYMAHKq8_y74WXWTT0pg9GsTYD9Fn1N5qzD6iDHXiO3lM5LGbXIlUS" "redirect_uri" => "http://localhost/integrations/nylasv3-callback" "code_verifier" => "e96bf6686a3c3510e9e927db7069cb1cba9b99b022f49483a6ce3270809e68a2" ] ``` response : `error":"invalid_grant","error_code":45004,"error_description":"Code verifier challenge failed` but getting code challenge is failed. I am doing everything in backend I need to get grant\_id and save from the last request and with api key I will consume endpoints. ---
**Author:** ![ram](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.nylas.com/ram/32/3_2.png) [@ram](https://forums.nylas.com/u/ram)\ **Post date:** [July 24, 2024, 8:13pm UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/5 "2024-07-24T20:13:48Z")
@efeengin for completing backend Auth, just curious is PKCE a requirement for your app? Also want to share our Quickstart guide with built in authentication, we go over how to [Set up user auth with Nylas](https://developer.nylas.com/docs/v3/quickstart/email/#set-up-user-auth-using-nylas). ---
**Author:** ![efeengin](https://avatars.discourse-cdn.com/v4/letter/e/3e96dc/32.png) [@efeengin](https://forums.nylas.com/u/efeengin)\ **Post date:** [July 24, 2024, 8:35pm UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/6 "2024-07-24T20:35:47Z")
no it is not but when I send request to /token and if I do not put code\_verifier . I get some error like " param code\_verifier is not sent etc " ---
**Author:** ![efeengin](https://avatars.discourse-cdn.com/v4/letter/e/3e96dc/32.png) [@efeengin](https://forums.nylas.com/u/efeengin)\ **Post date:** [July 24, 2024, 8:41pm UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/7 "2024-07-24T20:41:28Z")
what I meant is. I send /auth without code\_challenge and code\_challenge\_method which is withOUT PKCE. then I get the code. then I do 1 more request to /token to get grant\_id . if I do not send code\_verifier I get error. I believe something is broken with API. spent all day to try every combination still not good. ---
**Author:** ![efeengin](https://avatars.discourse-cdn.com/v4/letter/e/3e96dc/32.png) [@efeengin](https://forums.nylas.com/u/efeengin)\ **Post date:** [July 24, 2024, 8:42pm UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/8 "2024-07-24T20:42:52Z")
and all other endpoints grant\_id/messages etc working really fine. just stuck in authentication. ---
**Author:** ![Emmad\_Altaf](https://avatars.discourse-cdn.com/v4/letter/e/8baadc/32.png) [@Emmad\_Altaf](https://forums.nylas.com/u/Emmad_Altaf)\ **Post date:** [July 25, 2024, 11:10am UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/9 "2024-07-25T11:10:03Z")
Hi @efeengin @ram , I am also facing same issue from last two days, I am trying to exchange code but its giving me error that “Code verifier challenge failed”. I tried hard but its not resolving. I think there is an issue with api. If you got solution then please help me also. I am still stuck at this error. ---
**Author:** ![efeengin](https://avatars.discourse-cdn.com/v4/letter/e/3e96dc/32.png) [@efeengin](https://forums.nylas.com/u/efeengin)\ **Post date:** [July 25, 2024, 11:51am UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/10 "2024-07-25T11:51:28Z")
@Emmad_Altaf I believe it is API issue cause I tried any combination with and without PKCE I got same error everything. in my first try I was able to get grant\_id so I moved to implement other endpoints after 5-6 hours when I try to auth other account . I got that error and it still exists. ---
**Author:** ![efeengin](https://avatars.discourse-cdn.com/v4/letter/e/3e96dc/32.png) [@efeengin](https://forums.nylas.com/u/efeengin)\ **Post date:** [July 29, 2024, 6:21am UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/11 "2024-07-29T06:21:07Z")
@ram @Emmad_Altaf any progress cause I am still getting this error. I am pretty sure it is an API issue. Is there any [@admins](https://forums.nylas.com/groups/admins) who can look at thi issue? ---
**Author:** ![Emmad\_Altaf](https://avatars.discourse-cdn.com/v4/letter/e/8baadc/32.png) [@Emmad\_Altaf](https://forums.nylas.com/u/Emmad_Altaf)\ **Post date:** [July 29, 2024, 8:00am UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/12 "2024-07-29T08:00:18Z")
Hi @efeengin, I emailed Nylas support, and they asked me for details in their reply. I provided them with all the details last Friday. Hopefully, the Nylas team is looking into this issue. I am also waiting for the Nylas team to fix this issue as my work is currently halted because of it. ---
**Author:** ![efeengin](https://avatars.discourse-cdn.com/v4/letter/e/3e96dc/32.png) [@efeengin](https://forums.nylas.com/u/efeengin)\ **Post date:** [July 29, 2024, 8:35am UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/13 "2024-07-29T08:35:12Z")
I am waiting this issue to be solved also. ---
**Author:** ![ram](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.nylas.com/ram/32/3_2.png) [@ram](https://forums.nylas.com/u/ram)\ **Post date:** [July 29, 2024, 3:21pm UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/14 "2024-07-29T15:21:23Z")
Hi, thanks for sharing your debugging steps - let me block some time to take a look at this soon. ---
**Author:** ![efeengin](https://avatars.discourse-cdn.com/v4/letter/e/3e96dc/32.png) [@efeengin](https://forums.nylas.com/u/efeengin)\ **Post date:** [July 29, 2024, 7:48pm UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/15 "2024-07-29T19:48:08Z")
@ram any news? we really stuck here. ---
**Author:** ![ram](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.nylas.com/ram/32/3_2.png) [@ram](https://forums.nylas.com/u/ram)\ **Post date:** [July 29, 2024, 8:38pm UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/16 "2024-07-29T20:38:04Z")
@efeengin I’m going to try to authenticate using our [Quickstart Guide for Email](https://developer.nylas.com/docs/v3/quickstart/email/) as a test. Can you confirm if you have tried running one of our [Quickstart Guides](https://developer.nylas.com/docs/v3/quickstart/) with your App credentials and the result? You can also just download the repository, and add your credentials, and run it. Trying to determine where the issue is. ---
**Author:** ![ram](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.nylas.com/ram/32/3_2.png) [@ram](https://forums.nylas.com/u/ram)\ **Post date:** [July 29, 2024, 8:52pm UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/17 "2024-07-29T20:52:05Z")
@efeengin @Emmad_Altaf I was able to test out the following [Quickstart Guide](https://github.com/nylas-samples/quickstart-email-node) to authenticate and received a grant: `{"message":"OAuth2 flow completed successfully for grant ID: GRANT_ID"}` If you can try doing the same, we can futher debug where the issue is. All the code for authenticating is available in the [repository](https://github.com/nylas-samples/quickstart-email-node/blob/main/index.js) as well (and we have similar repos for other languages). Alternatively, can you try creating a test grant (`Add test grant`) using our Dashboard? This uses our hosted authentication UI screen, but is another way to test auth is working for your application without code: ![Screenshot 2024-07-29 at 4.52.25 PM](https://us1.discourse-cdn.com/flex015/uploads/nylas3/original/1X/2c2ba6fdd13288f46d183ece3fa1c3215cab785f.png) Another question - are you using our `sandbox` environment to test out Auth? ---
**Author:** ![efeengin](https://avatars.discourse-cdn.com/v4/letter/e/3e96dc/32.png) [@efeengin](https://forums.nylas.com/u/efeengin)\ **Post date:** [July 30, 2024, 8:18am UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/18 "2024-07-30T08:18:05Z")
yes I am using nylas sandbox env to test oAuth ---
**Author:** ![efeengin](https://avatars.discourse-cdn.com/v4/letter/e/3e96dc/32.png) [@efeengin](https://forums.nylas.com/u/efeengin)\ **Post date:** [July 30, 2024, 10:55am UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/19 "2024-07-30T10:55:57Z")
@ram funny thing is when I dont send any code\_challenge code\_challenge\_method. also code\_verifier for token endpoint I get code verifier not provided error. so every request for me goes over PKCE > {“error”:“invalid\_grant”,“error\_code”:45004,“error\_description”:“For code challenge check, code verifier not provided”," ---
**Author:** ![ram](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.nylas.com/ram/32/3_2.png) [@ram](https://forums.nylas.com/u/ram)\ **Post date:** [July 30, 2024, 1:26pm UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/20 "2024-07-30T13:26:57Z")
Hi @efeengin - can you try running one of our [quickstart guides](https://developer.nylas.com/docs/v3/quickstart/) to authenticate an account? I don’t suspect an API issue. Our quickstarts have all the code that you can compare across your application. Also can you share what your Callback URIs are, I want to check the `Platform` field: ![Screenshot 2024-07-30 at 9.26.24 AM](https://us1.discourse-cdn.com/flex015/uploads/nylas3/original/1X/87a180d6eebde3fae4627e2429b4682b2e452fc2.png) ---
**Author:** ![Emmad\_Altaf](https://avatars.discourse-cdn.com/v4/letter/e/8baadc/32.png) [@Emmad\_Altaf](https://forums.nylas.com/u/Emmad_Altaf)\ **Post date:** [July 31, 2024, 10:02am UTC](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291/21 "2024-07-31T10:02:12Z")
Hi @ram , Below are details: Client Id: CLIENT\_ID API key: API\_KEY **My application code methods - flow:** codeVerifier: CODE\_VERIFIER codeChallenge: CODE\_CHALLENGE nylasHostUrl: [https://api.eu.nylas.com/v3/connect/auth?client\_id=20f1c644-c0b1-4c62-b6ac-0109aad8fcd6&redirect\_uri=http://localhost:43344/api/Integration/EmailAndCalendarMasterAccountCallback&response\_type=code&access\_type=online&provider=google&login\_hint=nylasv3@gmail.com&code\_challenge=Ak2HC08a01ywI1CohFcVgmIV6CX11OjMown\_Nvj7WdU&code\_challenge\_method=S256](https://api.eu.nylas.com/v3/connect/auth?client_id=20f1c644-c0b1-4c62-b6ac-0109aad8fcd6&redirect_uri=http://localhost:43344/api/Integration/EmailAndCalendarMasterAccountCallback&response_type=code&access_type=online&provider=google&login_hint=nylasv3@gmail.com&code_challenge=Ak2HC08a01ywI1CohFcVgmIV6CX11OjMown_Nvj7WdU&code_challenge_method=S256) code: CODE json: {“code”:“CODE”,“client\_id”:“20f1c644-c0b1-4c62-b6ac-0109aad8fcd6”,“client\_secret”:“API\_KEY”,“code\_verifier”:“CODE\_VERIFIER”,“redirect\_uri”:“[http://localhost:43344/api/Integration/EmailAndCalendarMasterAccountCallback",“grant\_type”:"authorization\_code](http://localhost:43344/api/Integration/EmailAndCalendarMasterAccountCallback%22,%22grant_type%22:%22authorization_code)”} responce: {StatusCode: 401, ReasonPhrase: ‘Unauthorized’, Version: 1.1, Content: System.Net.Http.HttpConnectionResponseContent, Headers: { Connection: keep-alive X-Frame-Options: DENY X-Content-Type-Options: nosniff X-XSS-Protection: 1; mode=block x-kong-upstream-latency: 50 Access-Control-Allow-Origin: \* Strict-Transport-Security: max-age=63072000; includeSubDomains Accept-Ranges: bytes Cache-Control: no-store x-kong-proxy-latency: 10 x-unique-id: 1981e2a2-edf4-41ff-8e61-59e2fb22ca01 Via: 1.1 varnish, 1.1 varnish Date: Fri, 26 Jul 2024 09:40:40 GMT X-Served-By: cache-qpg120109-QPG, cache-qpg120109-QPG X-Cache: MISS, MISS X-Cache-Hits: 0, 0 X-Timer: S1721986840.087965,VS0,VE243 Vary: Origin Content-Length: 203 Content-Type: application/json }, Trailing Headers: { }} responseString: {“error”:“invalid\_request\_error”,“error\_code”:401,“error\_description”:“client\_id is required”,“error\_uri”:“[Nylas Unified Auth Service API Reference](https://accounts.nylas.io/#tag/Event-Codes%22,%22request_id%22:%22321fd5a0-dac5-4ce3-a7ca-df93d640c9c1)”} **Now I am also sharing PostMan call details:** [https://api.eu.nylas.com/v3/connect/token](https://api.eu.nylas.com/v3/connect/token) { “code”:“CJiO7tK4x0A5IYRw1XNiYcJ-IXMGZkrWKi–XOkuZ8S9oo0GyxpgUeBW8KJb\_S5e5XC3IIP4X7dIgEzjKMvIP4-ttIP5X-YA”, “client\_id”:“20f1c644-c0b1-4c62-b6ac-0109aad8fcd6”, “client\_secret”:“CLIENT\_SECRET”, “redirect\_uri”:“[http://localhost:43344/api/Integration/EmailAndCalendarMasterAccountCallback](http://localhost:43344/api/Integration/EmailAndCalendarMasterAccountCallback)”, “grant\_type”:“authorization\_code”, “code\_verifier”: “4ebk8Yi3piz7DVqayWFLd1HXX5YFlC4GmEKrphWftNU” } { “error”: “invalid\_grant”, “error\_code”: 45004, “error\_description”: “Code verifier challenge failed”, “error\_uri”: “[Nylas Unified Auth Service API Reference](https://accounts.nylas.io/#tag/Event-Codes)”, “request\_id”: “ee26a152-6092-49a7-8550-c5d6b6e69f77” } ![image.png](https://mail.google.com/mail/u/6?ui=2&ik=747154b37d&attid=0.1&permmsgid=msg-a:r-6343116732896790416&th=190ee783af70f767&view=fimg&fur=ip&sz=s0-l75-ft&attbid=ANGjdJ-iKIKEmuyY9jkTw-Frq1dMhUzBwLdDGlN8IGJNphZj5j18n0l1xruT-55vSBiLUwoYKNgD7wdjMcSzi-fE-kutjxQJcgQpPdCdepFLH148_xpRsnH-kmOgDAA&disp=emb&realattid=ii_lz2ilgl50) ![image.png](https://mail.google.com/mail/u/6?ui=2&ik=747154b37d&attid=0.2&permmsgid=msg-a:r-6343116732896790416&th=190ee783af70f767&view=fimg&fur=ip&sz=s0-l75-ft&attbid=ANGjdJ-pftRMpIYygtCZLCiC04vW724G_PjjHsUGVvqAO3rkmG2XBif-ov2H0IK78ePqCwPYZbWVP8KHcbaw5QeKC0YHmgEci8OCe_lmBY3dd2cuK22KHjiqkabJnSw&disp=emb&realattid=ii_lz2indjt1) ![image.png](https://mail.google.com/mail/u/6?ui=2&ik=747154b37d&attid=0.3&permmsgid=msg-a:r-6343116732896790416&th=190ee783af70f767&view=fimg&fur=ip&sz=s0-l75-ft&attbid=ANGjdJ-FuhAlU_KoTxb7Hp9c3GaoaJhEgAwZpk14AAcnD_QfEstSwybzkzRDcm_qEUEZEhw2Ia4GbPQ1EusFqBbczhiKTHFCogOXHCHuSmqvqPe195xZ1M4h3wnAH7I&disp=emb&realattid=ii_lz2io13t2) If i try with my application then its asking that client id is required , you can check i have already correctly passed client id. But if we run flow in postman with same data then its asking that Code verifier challenge failed. Please review this and investigate/test it in details - its always asking that “Code verifier challenge failed”, I believe this is api issue. I am waiting for your quick fix please. Thanks [Next page](https://forums.nylas.com/t/problem-about-post-https-api-eu-nylas-com-v3-connect-token-request/291.md?page=2)