Email Issue -Sharepoint WSS 3.0

Hi ,

I have a strange issue that im unable to fix, we have migrated from exchange 2003 to exchange 2010.

I had a distribution set for recieving email from the sharepoint WSS 3.0 (no MOSS) re access request to the sites etc.. when the sharepoint was pointing to the old exchange 2003 as an smtp server, emails alerts worked as expected. Since pointing it to the new email excahnage 2010 server as an smtp its not working, (even though when user request access from sharepoint it say request send successfully).

I have checked all the settings again and again and made sure the IP of the sharepoint is listed to relay through the exchange 2010- i have even specifed my own email address in the reply to address in sharepoint under outgoing e-mail settings to no avail?

Whats going on and how can i fix this?

p.s - Another strange thing is that alerts set in document library etc are working fine, using the very same distribution group. (we get alerts every morning of any changes)- so it looks like there is something wrong at the central administration level within the sharepoint...?

Thanks