I installed the recommend fix, restarted but the error is still there.
Nov 8 10:27:45 wimbornefolk dk_sign[1727]: Starting the dk_sign filter...
Nov 8 10:27:45 wimbornefolk dk_sign[1727]: DKIM error: DKIM Feed: Syntax error
Nov 8 10:27:45 wimbornefolk journal: plesk sendmail[1724]: Error...