Does not work with custom server anymore.
Does not even send a request and then times out.
It works with 8.11.2 so I reverted to that one.

Edit:
8.13.2 also works, so seems like you introduced a problem when updating to 8.14 which seems to have been a major update.
I went with 8.11.2 first because that was the version that is currently still working in thunderbird.
Not really keen on making an account just to report it.