Using Fedora 35 KDE and Thunderbird 91.4, I can no longer send from 2 of my 3 Verizon e-mail accounts (one of them is fine). The problem started about 3 months ago with one of the 3 and two months ago with the second.
Firebird's error message shows: "Sending of password for user
xxx.xxx@verizon.net did not succeed. Mail server pop.verizon.net responded [SYS/TEMP] server error. Please try again later."
Messages can be received from those two accounts, but not send. Using the accounts from the browser shows no error. Of course, the passwords have been checked and re-checked.
And it's confusing because one account is perfectly fine with Thunderbird. I had no problems when F-35 was installed in October.
Any clues to this problem are appreciated.