all filters not working anymore

My Filters do not work anymore.
history:
I experimented with qdbusviewer, afterwards, "akonadi_pop3_resource_0rc" 
created pop up error messages. I deleted this this in configure / Accounts and 
recreated it under the same name; the error messages went away and messages 
were deleivered into "Lokale Ordner/inbox" as expected.
problem:
the filters do not apply anymore, all mails are still in "Lokale Ordner/inbox" 
instead of being moved into different folders according to filter rules.
diagnostic:
1. Tools/Filter Log Viewer: All logging options switched on, manually started 
filtering ("Run Now in the Filter Rules dialog"), nothing happened, no output 
in the filter log.
2. Exported the filters, edited and re-imported one of them , no effect.

Any ideas?