While adding I am getting the error message:
You are attempting to move a contact from one address book to another
but it cannot be removed from the source. Do you want to save a copy
instead?
If I hit Yes the following message appears:
Error adding contact - Unknown error.

If y try to modify a contact the windows look very strange. All field
names are not highlighted (looks like read-only) and I can't add or
modify a content in any field.

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I deleted the GOA for Google and did setup a new one (same email
address and password).
It seems the problem did disappear as I could add/modify Google
contacts.

---

The problem is not solved...
I spent some time to figure out when it happens.
Here is what I found out:
After I did re-setup GOA it works absolutely fine.
The moment I check one of the boxes "Use in Birthdays & Anniversary
Calendars" or "Mark as default address book" in "property" of Contacts
(Google), the problem arises again...
For the moment I don't touch this boxes and it runs fine.

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From Milan Crha on Evolution List:

        Hi,
that's a good catch. The issue most likely resides in the evolution
-data-server, though also in the evolution, because it didn't claim the
error about failed open to the UI.

I see that after the change the corresponding contacts .source file
changes Authentication method to ClientLogin, while it should use
OAuth2. When I changed it to OAuth2 in ~/.cache/evolution/sources/<goa
-account-uid>/<another-uid>.source and restarted all evolution
processes, definitely evolution-source-registry, then the book begun to
work again.

I'd appreciate if you could file a bug against evolution-data-server in
GNOME's bugzilla with your description of the findings.

---

Rudolf