Company's Microsoft Exchange server in the network is hosted as Office 365 online services, when users try to access the mailbox, CFS doesn't allow connections to Microsoft Office 365 Outlook mailbox.
Resolution for SonicOS 6.5
This release includes significant user interface changes and many new features that are different from the SonicOS 6.2 and earlier firmware. The below resolution is for customers using SonicOS 6.5 firmware.
In this case, we need to white list the domains which are supported by Microsoft Office 365 Outlook.
Click Manage tab.
Navigate to Security Services | Content Filtering and make sure it is enabled and a CFS policy is applied.
On appropriate CFS policy, check the Profile associated (CFS Default Profile in this case).
Go to Objects | Content Filter Objects | CFS Profile Objects tab and edit the Profile above.
Click Create new URI List Object.
In the URI list enter the each of the following domains and click Add.