The character no longer move and play animations after I deleted some frame

When I duplicated an animation and deleted some frames to make a new animation,then I let my npc Character to play it,it no longer move and just stuck and the first frame pose forever!
I try another duplicated one but not edited,It can play.
What’s the problem of this?

for anyone having this issue, my only workaround was to reimport the animation i want to use, but set the range of frames i need. this is considering you are not willing to redo the animation on your specialized program or are just prototyping and need some kind of template.