Hi You may find several answers to this issue here on the Mozilla support forum. Often it means you have more than one device connecting automatically to your online email. Try logging out of email and shutting down all your devices (actually turn them off). Then wait 30 minutes or so, or do this overnight, so the online server has time to clear out the multiple connections. Bear in mind, each online email service has its own maximum connections limit, and we don't know how many simultaneous connections are allowed. General advice is to set Thunderbird's limit to three - or if three does not help, go lower. You may also have too many folders syncing at the same time. Also, set Thunderbird not to check for new mail too often. Checking every 10 minutes may help.