App crashing when use fingerprint sensor

i am using fingerprint sensor in my app but sometimes when i scan the fingerprint then next screen open and app is crash. So what i do for it and also any suggestion for code for if fingerprint not match and retry for scan (i use timer block)
here is my blocks -

Do not use Close Screen block at Screen1
closing Screen1 means Closing Application.

just use open another screen
and remove If then condition blocks

but i use this block in my other apps and when i remove fingerprint blocks in this app then it works fine. so i think it is not a problem for app crashing.
it show a error “App keeps stopping” after authenticate the fingerprint.

then, show the blocks from your app where you got this error

i show the blocks in

when i remove the fingerprint blocks then app works fine but with FF sometimes app crash after open “home” screen.