the 10MB setting means it will not scan anything over that size, and is limited by the fortinets memory.
Under the protection profile though, there is an ' oversize' options, which if if set will block files that cannot be scanned (ie 10MB). So check the protection profile settings.
If it isnt that, try temporarily removing the protection profile from the outbound rule to see if this is the problem, or its something else. if the scanning is breaking it, then suggest you create a rule at the top allowing it to pass to xdrive only without scanning.
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