In case the customer is experiencing issues with emails not being sent, check SMTP log if there are attempts at all, if not,
ssh to the system,
cd /opt/pbxware/pw/usr/sbin/ ls -lah | grep msmtp -rwxr-sr-x 1 root 1001 121K Jul 8 2018 msmtp
If permissions are not as above, change permissions,
chmod 02755 msmtp