Green light flashing modem

For our Hub 3 green flashing lights usually means the VM network is down in the locality.
Login to the VM Hub menu and check for  "No RF Signal" on the first page seen after entering the password.

Other Hubs have different meaning for the various colours of lamps.

I can usually confirm a general outage looking at the Wi-Fi networks broadcasting local to us
and seeing all the VMxxxxxxx SSIDs have vanished.   Ask if VM is also down for the folks next door.

Check for known faults in your street

Call 0800 561 0061 – this is an automated number.

https://www.virginmedia.com/help/check/status/identification/identify

When a major fault first occurs it can take 15+ minutes for the outage to be reported on the phone / web link.

So do check again.