Non-Delivery of Calendar items

[mlc9]

I have the occassional user that gets NDR's when trying to send Calendar invite updates or cancellations to external recipients. Those same updates or cancellations make it fine to internal recipients.

When looking into the Exchange 2003 Tracking Center, it shows it being "Routed and Queued for Remote Delivery", and then the next hop is just an NDR report being generated two days later (two days being our attempt window)

The NDR doeesn't really offer much info, other than saying "Could not deliver the message in the time limit specified. Please retry or contacy sys admin". The strange part is that it only appears to be an issue with Calendar invite updates or deletions. When sending just a regular email to the very same external recipient, it makes it fine.

Thoughts?

 

[ntinlin]

How do your route your external e-mails? Directly to the recipients MX or via a service like Postini or MessageLabs.

If the former might be worth looking at the SMTP logs and seeing what the target MX was saying at the time.

neill