The reason is that the US ISP has been blocking Manx emails en-masse for the past few months, owing to what it claims are unacceptable levels of spam email from IP addresses within the Manx.net numbering system.
Manx Telecom is quoted as saying the problem stems from some of its users not having sufficient protection to prevent their PCs from being taken over by spam bots.
The good news is that Manx Telecom has been in in discussions with Comcast about getting the blockade raised, but the slightly bad news is that any ISP in the world can block email from another ISP if it
gets a lot of spam from that domain.
Good system huh?...