Hmm, that's Weird the only thing I can think of would be a Potential Firewall issue.
When your Computer is on your VM Connection is the connection set to Private / Public, or do you use a 3rd party Vendor like ESET, McAfee, Norton.
As for why it would work on 4G would be as its an entirely different connection with different settings. Something on the VM Settings on your PC is affecting this.
You can try in Outlook to find the Icon in the taskbar area, then Press Control on your Keyboard and Right Click the Outlook Icon at the same time. Click the Connection Status Option and when the box appears click Re-Connect
It forces loads the connections, and if you do this on the VM Connection should kick it into working. Failing that it could confirm some settings are messing about specifically with Outlook for that you may need to speak to an IT Professional if your Email is Work-related.
