I've got the same problem just now on all devices. I notice there is planned work for 21st June - maybe they brought it forward. Tried phoning Virgin Media, but not could not report a problem with email - just broadband - which they checked and said it is working - I know it is working cause I'm using it. When I rang up a second time, they tried to put me through to a person, but then said office was closed.
Hopefully it will be fixed when I wake up tomorrow. Would be nice to have more updates on the service status whenever there is a fault like this, or they have changed the scheduled upgrades!