Cannot connect to gmail mailbox

We recently migrated our email from Exchange to Google Apps. However, when I go into my Mail Server Settings and set up the account, MSP is unable to connect to the mailbox. I am using IMAP, the mail server address is imap.google.com on port 993. When I try to save the settings I get the following error message :

FAILURE :Email Settings saved successfully. But error occured while trying to check connection with mail server - Problem connecting to mailbox.

I can connect to the mailbox through gmail using the username and password I put into MSP so that doesn't seem to tbe the issue. Does anyone have any thoughts on why I cannot retreive emails from google?