I love Thunderbird and have used it on multiple computers, so I know I'm comfortable with the menus. Within the last two months I've setup several accounts on both Windows and Mac computers. However, today, I have one account that just won't settle in. It's a Googlemail account, which I've used before. In fact, I'm already using multiple other accounts that are both Google and non-Google on the same Thunderbird client. However, with this new gmail account, though I can add it in just fine and it authenticates without an issue, when I try to actually click on its inbox, I get an error: "The current operation on 'Inbox' did not succeed. The mail server for account <name> responded: Unknown command u81mb63282056ywe." Steps I have tried in debugging: * Removing and then re-adding the account, many times * Doing the above with Google's two-factor authentication on and off * Doing the above with Google's "less secure apps" option both on and off * Trying the account on a Macbook (I couldn't even get past the authentication step, no matter what I did) * Trying the account on an iPhone (I could not get it to 'take' as a Gmail account, but when I entered the data as an Exchange account, it finally started working and I can now read emails on my phone without a problem) Since the account does work on my phone, I feel like it should work on Thunderbird, but I'm at a loss as to which setting to tweak. I'm reluctant to do an uninstall and reinstall of Thunderbird, because I have three other mail accounts that are currently working fine, and if a similar error starting showing up with them (meaning if I were to have trouble getting the accounts re-added), it would put a serious cramp in my productivity. Any advice would be appreciated!