[Evolution] Providing credentials with OAuth2

[Patrick O'Callaghan <poc usb ve>]

Evolution 3.20.5

Having changed my Gmail account to using OAuth2 directly rather than
via GOA, I now see occasional errors like this:

Failed to connect calendar 'Gmail: Birthdays'
Credentials are required to connect to the destination host

But no indication of how to provide the credentials. My email on the
same account doesn't have this problem.

How do I get round this?

poc