I just tested, it only change to email somehow.
Now error message is "
Content-type: text/html; charset=UTF-8
Revive Adserver was called via the command line, but had no host as a
parameter." And command was
/usr/bin/php /home/serverusername/public_html/adserver/scripts/maintenance/maintenance.php www.domainwhereserverrun.com
One stupid question: Does that missing host refer to server and domain where adserver runing or host where ads are showed? But I tested that too, no effect.