Error dialog when setting up a POP3 account in Thunderbird 68

Originally created by @intrigeri on #17272 (Redmine)

Spotted while updating the test suite (#17269 (closed)), with a Tails built from ca2b6939.

After clicking “Done” in the account setup wizard, I see a pop up dialog:

title: “Error with account $EMAIL”
text: “The account $EMAIL is being processed. Please wait until processing is complete to get messages.”
button: “OK”

I’m inclined to not treat this as a blocker for 4.1 because:

Pressing OK, which is the only choice given to the user, makes the problem go away and then the email account can be used as expected.
It could be caused by ca2b6939, which we may decide to revert after 4.1 once we’ve finished the corresponding conversation.

Edited May 15, 2020 by intrigeri

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information