Thunderbird 128 not getting messages
T'bird (128.3.2esr, MacOs 12.7.6) suddenly stopped picking up messages from one of my two email accounts about a week ago. I can see the mail using webmail, and I have checked that the username and password are correct. Following instructions on this site, I have removed the password from memory, quit and restarted, after which "You will be prompted to enter a new password for the account" (which does not happen!)
When I select Get New Messages, nothing happens. No prompt for a password, nothing.
I am not using any antivirus programs.
T'bird has from time to time in the past asked me to confirm security exceptions for this site, but not recently. Has something changed in this area?