Hi according to Dr Google I'm not the first one to encounter this error below.
SpamAssassin: invoked with 'spamd -D -q -u filter' failed to load user (filter) scores from SQL database: SQL Error: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (13) Thus, I cannot read SpamAssassin preferences from the database. I checked for the sticky bit on mysql.sock. No change. I added all in /var/lib/mysql/ to the 'daemon' group. No change. I hope somebody here can help me. I'm pretty much lost with this. Thanks Philipp