Did you set up and use an “app password”, and also allow “less secure apps” on your gmail account? See: https://forum.k9mail.app/t/gmail-setup-could-not-finish/650 (e.g., the link on my first response in that item).
Did you set up and use an “app password”, and also allow “less secure apps” on your gmail account? See: https://forum.k9mail.app/t/gmail-setup-could-not-finish/650 (e.g., the link on my first response in that item).