How to download emails from the "unknown" folder?

[Eriliu]

Hello,

I've just yesterday begun using Fossamail. But now I have a problem.
I've added my two web.de accounts to it. It seemed to work fine. But for the second account, it doesn't import any emails, and even if there are new emails online it says that there are none. The settings for the two accounts look identical. I use POP3 for both. The problem doesn't disappear by re-adding the second account or by setting it as default.
I use Windows 7 64-bit.

EDIT: Without changing any settings, one new email was now found and downloaded by Fossamail. But new emails that arrived after that weren't found, and importing read emails still doesn't work.

EDIT2: Okay, I figured it out.
Reason is, it only sends me emails in the "friends" folder, none in the "unknown" folder. How do I change that?
For now I've simply set my web.de accounts to automatically move all new emails into the "friends" folder, but it would be better if I could keep the distinguishment between the "friends" folder and the "unknown" folder.
(I edited the thread title accordingly.)