"The name X doesn't exist in the current context" Error

Question

I am trying to solve "Secret Message" task, where all the letters in the sentence have to be changed to backwards version of the alphabet (A becomes Z, Y becomes B etc).

The error occurs that I can't understand. What does "The name X doesn't exist in the current context" mean? Here's the code:
https://code.sololearn.com/cmC0L4opawtb/?ref=app

Thanks.

Answer 1

Variable <newArr> was declared at line 23, inside a for-loop body block; and so it is not recognized at line 36.