Portal Home > Knowledgebase > Google Message Security > Imail 451 Can't connect to domain.com - psmtp
Issue
Mail delivery to an IMail server is slow or sender reports a number of "451 Can't connect to domain.com - psmtp" errors.
Resolution
IMAIL server's default configuration has a configuration enabled called "Auto Deny Possible Hacks".
Turn this Imail functionality off and use a firewall to control which IPs can connect to the server.
Additional Information
When the "Auto Deny Possible Hacks" functionality detects a possible hack, it prevents connections from the IP from which it detected the possible hack. In this case, the traffic is proxied from the actual sender through Postini, so it is blocking Postini.
Add to Favourites 
Print this Article
Keep up-to-date on new technology, and services as the industry changes.
