If you mean the Share Play function, then I believe that Sony has set a minimum upload speed requirement of 5Mbps and on the VM 50Mbps tier your upload speed is only 3Mbps.
If you are eligible for the free speed boost to 70Mbps (when available in your area) I believe it comes with an upload speed increase to 5Mbps. Otherwise you would need to upgrade to a higher broadband package as all the other tiers have upload speeds above 5Mbps.
Disclaimer - I don't work for Virgin Media. I'm just another VM user trying to help out so my answers may be wrong :-) If you do like my answer please mark it as helpful as it may help others My setup: Vivid 200 Optical fibre with Superhub 2 in modem mode connected to a Netgear R7000 router. Telewest/VM user since 2001.