Server-to-Server OAuth token endpoint returns invalid_request despite activated app and verified credentials

API and Webhooks
1

Environment:

  • Server-to-Server OAuth app, Account Level, Activated
  • App name: Sansone Medicare Zoom Registration
  • Account ID: LOjHe7L0Qdu0Bcj-vhAI1w
  • Scope: meeting:write:registrant:admin
  • Account plan: Pro (Named Host)

Issue:
POST requests to https://zoom.us/oauth/token consistently return:
{“reason”:“Bad Request”,“error”:“invalid_request”}

Steps already taken:

  1. Confirmed app is Server-to-Server OAuth type and fully activated
  2. Confirmed Account ID, Client ID, and Client Secret match the App Credentials page exactly (verified via copy-paste, not manual retyping)
  3. Regenerated Client Secret and retested — same error
  4. Tested grant_type and account_id as URL query parameters — invalid_request
  5. Tested grant_type and account_id as x-www-form-urlencoded POST body — invalid_request
  6. Confirmed Content-Type header set correctly to application/x-www-form-urlencoded
  7. Confirmed Authorization header uses correct Basic base64(client_id:client_secret) format
  8. Checked Account Management > Account Profile for an alternate Account ID — only an unrelated “Account Number” field exists there

Could someone from the Zoom team check whether there’s an account-level restriction or configuration issue preventing token generation for this account/app?

Thank you for your help.