My Thunderbird stopped receiving emails. I am on a Mac. I am posting here because I looked through the list here. Others had the same problem but the conversation is now archived. I tried the offered solutions and they didn't work. So having just fixed mine, I'm posting my solution. Go to System Settings. to Passwords. Unlock Passwords by signing in. There you find your email service listed. Click on it and check that that password matches the password on your account on your email services website. If it doesn't, fix it. Then open Thunderbird on the menu bar at the top, go to Settings ( not Account Settings.) Go to Passwords, to Saved Passwords, click on that and it will show you a list of your saved logins. Below the list, you can click on Show Passwords to see what's there. I had a bad password in there. (I had more than one password that had been saved for Thunderbird.) I deleted all Thunderbird passwords. Then I closed and reopened Thunderbird, clicked Get Messages, filled in the correct password when asked. Bingo. My email downloaded into Thunderbird.