Marketing Cloud Transactional Message API: scope_mismatch error when using refresh and offline_access scopes

Question

I am integrating with the Marketing Cloud Transactional Message API:

• Transactional Messaging API

I am setting up a Named Credential in Salesforce to connect to the Marketing Cloud API, and I have added scopes:

refresh offline_access sms_write sms_read sms_send event_notification_subscription_create

But I am getting an error of:

scope_mismatch

I believe all those scopes are correctly configured in Marketing Cloud Installed Packages setup.

If I remove refresh offline_access, it works.

The Marketing Cloud documentation:

• Authorization Code Reference

Says regarding scopes:

If you don’t include the scope parameter in the request, the token is issued with the scopes assigned to the API integration in Installed Packages. If you include the scope parameter and use an empty string for the values, the token is generated with no scope permissions.

Looking in the Chrome Network panel, I believe that if I leave the scope field of the Named Credential empty, it does not pass a scope parameter.

But, does that mean Salesforce will get issued with refresh and offline_access scope?

Are refresh and offline_access scopes supported within the Marketing Cloud Transactional Messaging API?

Answer 1

refresh and offline_access scope are Salesforce Core scopes not Salesforce Marketing Cloud scopes.

Documentation about Marketing Cloud is terrible but according to these :

• REST API Permission IDs and Scopes
• API Integration Permission Scopes
• Access token app

In Marketing Cloud it seems that you always have the right to refresh your token and if you want a token that never expires, then you must use the scope offline. That's what I understood from the documentation, never tried.