NethServer release 7.5.1804 (final) Rspamd: 1.7.7 version
i dont get it how rspamd works or why spam is not rejected. I got every day from the same Senders Spam but sometimes it is rejected, sometimes greylisted and today nothing happen. See:
Is it a gmail address, for instance gmail sends email with a from address like firstnamelastname@gmail.com even if the email is firstname.lastname@gmail.com, of course since we do a regex of the email field, it must be exact.
As far as I understand the Bayes filter only uses the message content for filtering, not the sender address. So it should be the right one to do the job.
It does not outright flag messages as spam if they contain a specific subject, or sender address. It is only collecting specific characteristics of the message.
Did you check the logs to see if rspamd learned and the symbols of the mail in the history of rspamd web interface as @stephdl suggested?