Termite728; Over a 6-week interval, the problem diminished and ceased on the problem machine. All is well at this point with Thunderbird across my units servicing multiple outlook accounts on each. In my opinion the mail provider is the primary suspe...
in my case,Thunderbird A migrated to current upgrade with some hassles with Microsoft concerning access. In that instance Tools-AccoutSettings SMTP Oauth2Thunderbird B migrated to current upgrade with persistent failures. I removed saved login/passwo...
