The max hop count was exceeded for the message. This code may occur if a loop situation exists between a sending server and ...

{4}: The max hop count was exceeded for the message. This code may occur if a loop situation exists between a sending server and a receiving server that are not in the same organization. In this scenario, the message bounces back and forth until the hop count is exceeded. The max hop count property is set for each virtual server, and you can manually override this setting (the default setting is 15 for Exchange 2000 Server and 30 for Exchange Server 2003). Additionally, look for any situations that could cause loops between servers.