Oyster/UTS error code 76
 

First Capital Connect were using platform 1 at London St Pancras
today, so I took the opportunity to see if the gateline there (fitted
with ITSO pads) would accept my Oyster card on PAYG.

It didn't - I got the red light and error code 76, almost 3 seconds
after a 'touch-in' attempt. #76 must be new because it's described as
a 'spare' when I Google it, what does it mean now?