Absolute path

src/freedombone-app-mailpile

     echo 'User=mailpile' >> /etc/systemd/system/etherpad.service
     echo 'Group=mailpile' >> /etc/systemd/system/etherpad.service
     echo "WorkingDirectory=/var/www/$MAILPILE_DOMAIN_NAME/htdocs" >> /etc/systemd/system/mailpile.service
-    echo "ExecStart=./mp --www=0.0.0.0:${MAILPILE_PORT} --wait" >> /etc/systemd/system/mailpile.service
+    echo "ExecStart=/var/www/$MAILPILE_DOMAIN_NAME/htdocs/mp --www=0.0.0.0:${MAILPILE_PORT} --wait" >> /etc/systemd/system/mailpile.service
     echo 'Restart=always' >> /etc/systemd/system/mailpile.service
     echo 'RestartSec=10' >> /etc/systemd/system/mailpile.service
     echo '' >> /etc/systemd/system/mailpile.service