The other day we started to recieve NDR's for calendar invites when sent from Entrouage. Exchange 2007 is running off SBS 2008. When any user from Entrouage tries to send a calendar invite they recieve and NDR with this error. #554 5.6.0 STOREDRV.Deliver.Exception:ObjectValidationException; Failed to process message due to a permanent exception ## If an outlook user sends calendar its works just fine as well as from OWA. The problem started on Wednesday. So wednesday night I upgraded to Exchange 2007 SP2 and there is still a problem with it. Tonight I will do the upgrade to SP3 if I don't get any feedback from this problem. Thanks

Hi, How is the issue now? Regards, Xiu

Looks like SP3 has resolved this issue. I am not getting NDR's from this matter anymore.