title: Thunderbird: Keeps asking me to add security exception
body: <p>I've been using Thunderbird for ages without any (real) problems. A few days ago, Thunderbird updated to version 78.5.0. Shortly thereafter the problems started. I can't remember if it started immediately after the update so I'm not sure if the update was the direct cause.</p>
  <p>Anyway, every time I try to retrieve my mail (by clicking &quot;Get Messages&quot;) a pop-up appears:</p>
  <p><a href="https://i.stack.imgur.com/89ChC.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/89ChC.png" alt="Security Pop-Up Thunderbird" /></a></p>
  <p>This pop-up isn't new to me since I'm using my own mail server with a self-signed certificate. So every time I update the certificate, I get this popup. It <em>is</em> new however the pop-up appears while nothing has changed (other than Thunderbird updating).</p>
  <p>If I click &quot;Confirm Security Exception&quot;, the popup disappears but no mail is retrieved. If I click &quot;Get Messages&quot; again, the pop-up reappears. Oddly enough, If I go to Thunderbird's Certificate Manager, I see the certificate was actually added.</p>
  <p>So that's one strange thing. It isn't the strangest thing however. What's even stranger is that the location (email.glasshouse.nl:995) isn't the address of my mail server. If I look under Thunderbird's &quot;Server Settings&quot;, I see the correct address. Even if I change the server address to something else (the IP address for instance), the pop-up still displays <strong>email.glasshouse.nl</strong> as location. I'm not worried this is some kind of hack or virus or malware since I recognize the address - it's the mail server I used well over ten years ago (in Thunderbird).</p>
  <p>So what is actually going on here? And more important, how can I solve this so I can get to my email again?</p>
  <p>Thanks in advance!</p>