[Skunkworks] Outlook Not Receiving Mail

Hi Skunks, I have a queer problem where users on the outlook cannot send and receive mail [Send/receive error]. This has been a pain for more than two days and i cant seem to find a resolution. Facts: 1. The mail is corporate gmail and accessing it from the web is possible, but just not acceptable. 2. Google Sync can eliminate the problem but am using it only as a temporary measure. Any ideas welcome