Couple of years ago we played Northampton in the Carabao cup (first season back in champ with hecky) and the game was paused for a few minutes as the GLT had failed and the referee had to inform both managers and the 4th official had to go down the funnel to inform the EFL/FA. If the managers did not agree that the match was ok to continue then the referee CAN abandon the game, although I think this rule has now changed. They then had to put a brief message up on our state of the art 32inch LED TV in the corner of the away stand to let the fans know what was happening.
If I remember right, at home to Swansea last season Ayew scored a header for them and that had to be checked that it had gone in.