The Trophy is a competition for non-league clubs but last season's tournament is still to be completed, with the Sulphurites due to face Conference South side Concord Rangers in the final.
The FA had hoped to play it after fans were allowed back into stadia but Harrogate keeping alive the chances of reaching the League Two play-offs and the demands on Wembley it was not possible to play the game after the planned May 17 return of limited numbers of spectators.
Instead it will be played on the May Day bank holiday Monday, two days after Harrogate's league game at home to Cambridge United. The FA Vase final between Consett and Hebburn Town will be played the same day.
This season's Vase has been put on hold because of the latest lockdown, which clubs below Conference North/South level were not allowed to play through, but will resume with the third round proper on April 10, and be played to a May 22 conclusion. Again, the 2020-21 Trophy final will be played on the same day.
All four finals will be shown live on BT Sport.
Harrogate reached Wembley for the first time in their history in August 2020, when they beat Notts County in the Conference play-off final to win promotion to the Football League, which they had never before played in.
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