# Getting {'code': 124, 'message': 'Invalid access token.'} when calling /chat/users/{userId}/messages/files. How to fix the problem? **URL:** \ **Category:** Chat\ **Created:** [November 8, 2022, 11:03am UTC](https://devforum.zoom.us/t/getting-code-124-message-invalid-access-token-when-calling-chat-users-userid-messages-files-how-to-fix-the-problem/78461 "2022-11-08T11:03:44Z")\ **Posts on this page:** 1\ **Showing post:** 14
**Author:** ![elisa.zoom](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/elisa.zoom/32/47836_2.png) [@elisa.zoom](https://devforum.zoom.us/u/elisa.zoom)\ **Post date:** [March 17, 2023, 2:58pm UTC](https://devforum.zoom.us/t/getting-code-124-message-invalid-access-token-when-calling-chat-users-userid-messages-files-how-to-fix-the-problem/78461/14 "2023-03-17T14:58:06Z")
Hi @tech5 Thanks for sharing more details with us and sorry that your post got deleted and that you are having trouble downloading the API spec We have a Postman public space that you can use to test, please refer to the following post: > [@Zoom API Testing Made Easy with Postman Public Workspace](https://devforum.zoom.us/t/zoom-api-testing-made-easy-with-postman-public-workspace/75062): > > Article originally posted on [dev.to](https://dev.to/zoom/zoom-api-testing-made-easy-with-postman-public-workspace-5fh7) If you’re a developer or technical decision maker using Zoom APIs to: hammer_and_wrench build a customized video communications experience or, speaking_head tell impactful business intelligence stories, …it’s now easier than ever to test those APIs in a curated way! We’ve created a [Postman public workspace](https://www.postman.com/zoom-developer/workspace/zoom-public-workspace/overview) with done-for-you workflows to get access to and make streamlined requests to Zoom API endpoints. [Image description] How to Use Zoom’s Public … I also want to share this post about how to user the Server to server oauth app with postman: > [@How to user Server-to-Sever OAuth app with Postman](https://devforum.zoom.us/t/how-to-user-server-to-sever-oauth-app-with-postman/70848): > > How to use our Server-to-Server OAuth with Postman? As some of you might be aware of, our JWT app is being deprecated by June 2023 and we encourage you to migrate to the newly introduced [Server-to-Server OAuth App](https://marketplace.zoom.us/docs/guides/build/server-to-server-oauth-app) That being said, here is a quick and simple guide on how to use or new app with Postman As stated in our documentation here: This new app type facilitates OAuth-authenticated requests between servers without end-user involvement. And this grant type enable your private server a… I hope some of this information help --- _[View the full topic](https://devforum.zoom.us/t/getting-code-124-message-invalid-access-token-when-calling-chat-users-userid-messages-files-how-to-fix-the-problem/78461)._