We are currently experiencing problems with the trainable spam filter (Dspam) due to ongoing server upgrades. We expect these issues to be resolved by tomorrow (Tuesday, 06-Nov-2018). In the meantime, the basic spam filter works normally but you may see more spam coming through and we apologize for the inconvenience this causes.
Update 07-Nov-2018 13:09 CET: Dspam has been re-enabled now. Apologies for any inconvenience caused.