# Use trace to debug what clamd is doing:
strace -p $pid
# Or check postfix maillog
tail -200 var/log/maillog | grep clamd
Apr 14 00:19:45 server clamd[26194]: LOCAL: Socket file /var/run/clamd.amavisd/clamd.sock is in use by another process.
# Temporary solution, restart clamd:
systemctl stop clamd.service
rm -f /var/run/clamd.amavisd/clamd.sock
systemctl start clamd.service
