Error adding new email account

Hi!

I’m trying to add another email account to my Thunderbird client,
running on Ubuntu. It’s all in Swedish so the concepts here are my
translation.

I go to Add account and fill in the details. Then I do manual
configuration to edit the ports for IMAP and SMTP. And I click on OK.
THen I get an error, a red bar above the Server Settings section, saying
“Error in creation of account”. Nothing else.

So I click on Advanced configuration at the bottom of the page. THis
tells me that the account will be created even though not functional. I
click OK - and nothing more happens. And there is no account in the main
page.

Anyone got advice on what to do here and what goes wrong?

Magnus Larsson