Background on the problem: I work for a company which is a Panasonic Partner. As a part of this program, Panasonic regularly sends out "Partner Alerts" to everyone who is signed up to receive them. We have two users on our exchange server who are not receiving this email - when I contacted the reseller support, I'm told the emails are bouncing every time which is causing them to be added to a suppression list. Once removed from the suppression list, the next email bounces and none get through. I've asked them if they can provide the error message in the bounce back email and they said they don't have access to that. I've seen a screen shot of the suppression list, both email addresses are entered correctly (free of spelling errors).
The only difference I can see between these two users and everyone else is that on the exchange server, these users have random numbers following their "Windows domain\user name" where none of the other users seem to. I'm not sure where these numbers came from as all of the users were set up the same way.
Example: normal user is COLLABORATION\username
user not receiving these emails: COLLABORATION\username250
the alias and login are both correct (just username, no numbers) and neither of these users have had issues receiving email from anyone else (and one of these users receives hundreds of emails a day) Could this be the reason that the users are not receiving emails? The sender has been white listed on the exchange server for spam and such, and as I said there are at least 5 other people receiving these alerts with no problem.
Update: I found one user who also has numbers after the username and he receives the emails, so I guess I can rule this out as being the problem. They reported a hard bounce but the email address is definitely valid...any idea what could possibly cause this?