BACKGROUND:
A few days ago (04/05/21), my AT&T email account, which I access through Thunderbird 78.9.0 (64-bit), stopped downloading emails. Thunderbird showed a message box with the message
"Sending of password for user ******@att.net did not succeed. Mail server inbound.att.net responded: Server error - Please try again later."
After many tries with no change in 24 hours, I recalled a vaguely similar situation last November on our iMac...
