Problem with IMAP Mail account

My K9 does not load several IMAP folders. It states -loading-, but nothing happens. Inbox is pretty working, but folders, which are not offen used dont load. What to do? Any hints?
Best regards

What are the folder classes?

Which classes are set for push and/or pull?

Dear tchara,
I see folders only, no classes. All folders are set to call all News, Push/pull are also set top all folders.
Regards buni

In the folders overview, you can assign classes (none, 1st class, 2nd class) to the folders.

In the push and pull settings, you can assign those classes (all, 1st class, 2nd class, 1st and 2nd class).

K-9 will only actively pull or be pushed from the selected classes. Thus, only folders within those classes will be considered by K-9.

OK, thanks.
Will see If IT works
Regards buni