Context:

Email print is configured with Microsoft Oauth2 Modern Authentication

Issue:

When testing the connection error AADSTS50034 is returned

Open connection failed AADSTS50034: The user account {EmailHidden} does not exist in the e4c1b3fa-9ae1-44e1-ab35-3b127835cf26 directory. To sign into this application, the account must be added to the directory.
Trace ID: 3ccb4b66-cf5a-4544-b04f-98051bca7100
Correlation ID: 5982ba61-fe8c-4608-a134-37d2fa21985e
Timestamp: 2021-11-01 11:57:13Z

Resolution:

Make sure to follow instructions in section 18.8 of the manual > step 9. Choose Yes under Allow Public Workflows and click Save to save changes.