I have been using K-9 for nine years now.
I use version 5.600 under Android 7.1 on a Sony Xperia Z5 Premium with imap4.
Until two weeks ago I could see email having been filtered to the folder Spam by my IMAP4 server at Ionos.
Then I got a notification about an email that was filtered to the folder Spam by Ionos.
I synced my Spam folder via K-9, but it appears empty.
K-9 states it is synced.
But when I look at my Spam folder via a webclient, Thunderbird or Pegasus Mail I can see all the emails in the folder Spam.
Only K-9 seems to hide its content.
This problem didn’t happen before two weeks!
I phoned Ionos, but they told me that they didn’t change anything and it must be a problem with K-9.
How can I solve this, so that I can see the emails in the folder Spam again?
What might be the problem here?
It doesn’t occur with my other accounts e.g. GMX in my K-9!