County were easily brushed aside by a clinical Harrogate side, inflicting their heaviest National League North defeat in over two seasons.
Two goals either side of half-time were enough to easily see off the Hatters, who were given brief respite in the first half through a Chris Smalley goal.
All goals appeared preventable or came about via a mistake from the away side, as four different Town scorers put themselves on the scoresheet.
Gannon will be hoping to put a nightmare four days behind him and the team, after successive losses to Southport and now Harrogate.
FT: Harrogate 4-1 Stockport County
Scorers: (Harrogate) Emmett, 24; Thomson, 39; Knowles, 59; Kennedy, 67, (County) Smalley, 35.
Squad: Ormson, Cowan, O’Halloran (McKenna, 61), Ball, Smalley, Stott, Thomas, Winter, Oswell (Duxbury, 46), Stopforth (Dixon, 75), Stephenson.
Unused: Warburton, Hinchliffe