so the espresso was hot? did the machine get hot it would have to be hot to get the group head hot?
it does not seem possible that you had a hot espresso but did not have any steam or hot water?
did your antivac fail and you just had false pressure....., on 2nd thought it would get "hot" but not get really hot with steam if it was false pressure via a failing antivac.... and as pressure pushes out he water no pressure would mean no hot water..... (in my brugentti anyway)
did you try bleeding of any false pressure then seeing *if it started to get hotter?