In outlook 365 with the latest version of Gpg4Win (3.1.3) installed and thus the latest GpgOL
When composing a message and checking the names in the TO field by pressing ctrl+k outlook shows the address book.
Also a popup shows from GpgOL:
Failed to resolve recipients.
This is usually caused by a bug in GpgOL or an error in your setup.
Please see https://www.gpg4win.org/reporting-bugs.html or ask
your Administrator for support.
Same popup as a screenshot