I verified your puzzles, buddy.

According to chess analysis engines, some puzzles have more than one "solution". So in many cases, your little app says wrong when its right.
One of them was basically asking me to solve 5 moves in row that were not forced on either side. If you want people to find the only solution, make sure theres just one answer

Bingoxz about Chess Tactics Pro (Puzzles), v1.05