Hi david64, I think the following link gives a workable  solution to the problem that Thunderbird v78 will not download or send TPG emails: https://support.mozilla.org/en-US/questions/1295861   Especially see the comment by kotouc74 and also the comment by Wolfgang Scherer.   So, to combine their advice into one procedure that will work for the TPG servers: In Thunderbird, select Tools, then select Options At the top of the page, in the Find in Options search box, enter “Config Editor” and the hidden link to the Config Editor should show. Click on the link.   Note the warning “This might void your warranty!” and click on “I accept the risk!”   Search for “security.tls.version.min”, double click and set value to 1 (Default setting is 3 if you ever need to back track)   Search for “security.tls.version.enable-deprecated” double click and the setting should change from “false” (default) to “true”.   With TPG, I’m using Port 110 to connect with the POP mail server and Port 587 to connect with the SMTP server. For both servers, the Connection Security is set to STARTTLS.   With the above settings, while TPG email encryption is not happening at current “best practice” due to TPG policy, it is no worse than before. Also, it is considerably better than one TPG suggestion of setting Connection Security to None.   I agree the best solution is for TPG to update its encryption protocols to current “best practice”.   ... View more