I recently upgraded from Thunderbird 68 to 78 and my main email account, a pop3 account, can send but can no longer receive emails. The error message is currently: "An error occurred with the POP3 mail server. Mail server mail.tpg.com.au responded:" I have tried many fixes suggested in these forums, including deleting the saved password linked to the account, in the hope of re-entering it. Thunderbird now does NOT ask for a password when I check mail on this account, but just gives the error message above. My IMAP accounts are working fine on Thunderbird. The POP3 mail server also works when accessed through webmail or the email app on my phone. The ISP (TPG) assures me that their mail server is working normally. I downgraded to 68.10 and the problem persists. I would be very grateful for any ideas on how to fix this! Thanks in advance.