We've been migrating from Exchange 2003 to Exchange 2010. In following the steps to replicate free busy time, offline address book, etc. Last night I removed the replication between the two servers and only had the new Exchange server listed. This AM when staff is sending calendar invites OUTSIDE our network, the Accept, Tentative and Decline buttons are not longer on the invite, inside network it shows those buttons, it looks like a regular email. I have since place back the replication between the two servers, but not sure if this is root cause of issue.