At the SMTP level, Mercury is very strict on proper addressing standards being used. This dates from the days of "services" like ORBS, that would try to trick a mail program into relaying mail, often using tests that involved addresses in illegal formats.

In a plain mail message, having an address without "<>" is generally OK, but in the SMTP transaction state, it's quite illegal, and it's my guess that this is where the problem is occurring in your case. Your best bet is to get the application generating the faulty addressing corrected.

Cheers!

-- David --

I've noticed an issue when one of our clients sends an email and the to address has no <xxx@xxx.xxx> included

eg: support@domain.com   instead of   <support@domain.com>

The first fails, the second works.

Why ?

Thanks
 

First is not valid RFC format.

Thanks Peter

Just checked the RFC Specs.. Looks like a faulty application.

I'll let the developers know. 

We would need to know more about their email environment.  Certainly, sending an email to support@domain.com works perfectly for us; Pegasus Mail and Mercury both know how to handle this directly.  Any diagnostics files would be helpful, such as Mercury or Pegasus Mail TCPIP transaction logs.