Some additional information - i restarted my computer to see if that made a difference - it did not. I then shut it down and restarted it to see if that made a difference - again, it did not. I am able to send emails without a problem, though.

https://support.mozilla.org/kb/cannot-receive-messages

Went to the message sent above and tried what was recommended. No luck. Still cannot receive emails. Verified that my pop mail account settings are correct.

We have two computers, both of them using 52.5.0, and both of them getting emails just fine. One of them suddenly started getting the "failed to connect to server" message, even though I haven't changed any settings in TB. Just to be clear: Both computers share a common email address, and those emails usually show up on both computers. Suddenly one of them receives the emails while the other does not.

NCjohnL,

please start a new topic for your problem. https://support.mozilla.org/questions/new

Well, don't know what happened, but today, Thunderbird asked for my password which I entered and all is now fine. After repeated failed attempts to hook up to my ISP, it suddenly started to work. Can't explain why, but the issue is now resolved!

I still cannot receive messages after doing all you suggest