[Evolution] Stuck on fetching POP3 mail, how to debug?

[Martin Wagner <mwrsa web de>]

Hey there folks,
here I am with another issue I have no clue about how to solve:

Every so often Evolution gets stuck completely on fetching mail,
usually from the same three of my seven mail accounts. It's on the POP3
mailboxes only, and while one is a German freemail service, the other
two are on my own server. Nothing really helps but to forcibly close
Evolution, and when I restart it the emails in question are marked as
"read" on the server (checked via webmail) and will no longer be
downloaded. In some cases this is crucial if it's bills for my
business, which I need to receive ofc., and archive.

Now every other application I would start from the command line and
watch the (error) output when things like this happen. Not so with
Evolution - there is no output whatsoever.

Simple question: What can I do to solve this?

Thanks in advance for any helpful contribution.

Basic info on my system: Mint Mate 20, all updates installed, Evolution
3.36.3-0ubuntu1
The same issue existed before the upgrade from Mint 19.3 to 20,
probably even with earlier versions, but it's happening more often and
with more important emails recently.

Cheers, Martin