Esign won’t work for one user

We have 3 user licence for acrobat dc.  Esign works fine for 2 and NOT AT ALL for the third

all our security is the same, all settings in dc are the same, acrobat have been on the phone approx 8 hrs all up and have no clue why it won't work.

anybody any ideas?  If Adobe have no idea who on earth is supposed to know.  Fed up of being out on hold, passed to numerous customer service reps ... a better alternative to Adobe anyone?  This has lost my business at least eight hours work paid work 

not cheap either wasting money and getting very very fed up