Invalid access token in Production

Currently im facing the following issue:

When I want to create an envelope in the production environment I get this error:

Error calling CreateEnvelope: {"errorCode":"USER_AUTHENTICATION_FAILED","message":"One or both of Username and Password are invalid. Invalid access token"}

The get user info endpoint, which also takes the access_token, still works in the production env, right after this call I call the create envelope endpoint, and the jwt token expire time was set to 1 hour so an token expiration is not the issue.

When I try the same code with the same App in the demo environment it perfectly works.
 

Settings in production env:

• I created a new RSA key
• I granted the access for the app with the User (Admin) I want to impersonate (signature and impersonation).
• I changed the userId to this user
• I changed the Base Path to account.docusign.com
• I changed the accountId to the production accountId.
• The clientId remained the same

Are there any additional settings (Organisation with SSO, Account) that have to be set?