This is a solution for a problem that has recently arisen. After upgrading to TB 78.6.0, I began to get errors like in the subject line above whereby inbound service wo… (read more)
This is a solution for a problem that has recently arisen. After upgrading to TB 78.6.0, I began to get errors like in the subject line above whereby inbound service worked fine but outbound crashed. After much fiddling about with Win10 security settings (virus, firewall, etc), I noted that wife's separate acct had similar issues (thus, not machine specific) and that outbound service still worked from Comcast's online app (thus, not truly an acct issue).
I finally stumbled on the solution: in TB Outgoing Server settings, I had, for some arcane reason, two smtp.Comcast.net servers listed. The Default one had my actual username listed for username, while the other had my "extended" full username@comcast.net. Apparently, TB was trying to authenticate with the second, full address. When I edited the username and dropped the "@comcast.net," TB works.
Since the same fix worked on my wife's separate acct with the same issue, I presume the latest TB update (78.6.0) must have tightened some security authentication or some similar scenario was implemented at Comcast.