If your IGT S+ reel slot machine is displaying an error code in the Winner Paid window, please see the following link for a list of common S+ error (tilt) codes, along with the steps needed to resolve the error:
/igterrors/(This link can also be found in "
Rick's FAQ Files" from the old NLG.net site.)
Edited to add:
IGT S+ error 63 (not listed in the above link) -- see
this thread for details.
IGT S+ error 64 (not listed in the above link) -- communication link down (typically when an S+ machine isn't communicating with an add-on bonus unit like a Barcrest or AC Coin bonus feature) -- see
this thread for one possible solution.