For a few days now, synchronization and opening new messages from a Gmail account configured in Thunderbird have been very slow. I use Thunderbird 140.x, which is regularly updated, and the mailbox has been configured for at least 5 years. Only in the last week has the problem emerged, rendering it unusable. Timeout errors and opening a new message after 2-3 minutes. I've cleared the cache, the database, and re-indexed, but nothing has changed. I've deleted and reconfigured my Gmail account, but nothing has changed. My Gmail mailbox is about 45 GB (I've seen much larger ones without losing performance). I tried installing Thunderbird on a new, clean PC, but the same thing. Extremely slow. Google support hasn't found any issues. Do you have any other suggestions for getting Thunderbird back up and running? Thanks.