It's in the Frankfurt area squawking a normal code ATM, 5236 FWIW, so any loss of comm must have been brief.
You can get a lot of frequency changes coming out of London and heading into Europe as you hop from one controllers box of airspace to the next, to the next etc and just occasionally a change gets missed....it usually gets sorted out fairly quickly by various methods (for example calls on the emergency frequency, which is always meant to be monitored), it rarely escalates into a major problem but it has happened.