JWT Authentication Failing After Integration Key Promotion - issuer_not_found Error

Description:

I'm unable to authenticate using JWT Grant with my promoted integration key in production. I receive an issuer_not_found error despite having the integration key properly configured.

Configuration:

• Integration key was created in developer account and promoted to production using DocuSign's go-live process
• Generated new RSA key pair in production
• User Application setting: Yes
• Authentication Method: Authorization Code Grant
• Redirect URI: http://localhost:8080/callback

Error:
When attempting JWT authentication, I receive:

{"error":"invalid_grant","error_description":"issuer_not_found"}

Steps Attempted:

1. Tried granting individual consent via multiple authorization URLs (both account.docusign.com and account-d.docusign.com)
2. All consent URLs fail with "The client id provided is not registered with Docusign"
3. Verified all User ID, Account ID, and Integration Key values match between production account and application configuration

4. Confirmed RSA key pair is properly configured

5. Attempted granting consent via authorization URL provided by Docusign support (Token endpoint: account-eu.docusign.com/oauth/token). Account-eu.docusign.com does not resolve in DNS either in USA or EU (attempted on 4 different devices, in 4 different global locations)

UPDATE: I've tested authorization from both US location (original) and EU location (IP 9.160.161.135). Both locations return the same error: 'The client id provided is not registered with Docusign.' This confirms the issue is NOT geo-routing.