When making an API call I receive a 401 error?

When some or all API calls start returning 401, this means that the Nylas token or provider credentials or both are invalid. 

If only /send, /file upload and some other POST calls are returning 401 it is the provider's credentials that are invalid. In both cases, the user needs to re-auth.

Error Response:

{
 "message": "Could not verify access credential.",
 "type": "invalid_request_error"
}

Causes

• Invalid credentials
  
  • The provider is asking for a multi-factor authentication to renew the token.
  • You can also check the Dashboard sync logs to find any errors in renewing access tokens.
• The token used for the API request does not have permission to the relevant scopes.
• The token is revoked or is expired.

Resolution

• Re-authenticate
• Make sure that the token has all the relevant scopes to do the API request.
• Make sure the token is valid Check token info

Resources:

How to handle accounts going into stopped or invalid state.