I had someone contact me yesterday and say that their email to me is bouncing. They are using Outlook.com, and getting a fairly generic bounced message:

This is an automatically generated Delivery Status Notification.
Delivery to the following recipients failed.

There's no error number or specific error message; just that it failed.

I had a friend log in to their Hotmail.com account, and they had no problem emailing me.

So, I went back to the original person, and asked them to email me through a domain that's parked on top of the one that bounced (an Add-on domain), and that email went through with no problems.

They can also visit the main website (the domain for the email), so pinging the domain through their own IP is no problem.

The only variable I can see here is that Outlook.com isn't pinging my domain properly, but Hotmail.com is.

So, I have two questions for you guys:

1. Have any of you seen a problem like this? Or is it isolated to me?

2. Any suggestions on how to track down WHY this is happening?