Dave Watson's side had been hoping to build on their win over Brighton, when Kelland Watts and Elias Sorensen were on target as United made it two wins and a draw from their four play-off games so far.
And confidence was high, as the Magpies recorded a league double when the two sides met during the regular season, winning 4-1 at Little Benton and 2-1 in the Black Country.
But the game has now been postponed and Newcastle's next game at this level is away to Leicester on Saturday, 29th April (kick-off 11am).