I have a kegerator, this is the first keg I have taped. It started out with a little to much head, then came good. after about 6 glasses it stopped pouring at all. can anyone advise me on a solution? I tried bleeding the co2 and had my regulator set to dispensing pressure, It just seams to expel gas from the tap, then nothing. the beer line has beer in it but stops just short of the keg.