Android build errors?

[rohaninina]

I keep on getting these errors whenever I try to build the android version of my game but i don't know what they mean? i'm new to coding so any help is appreciated. i use renp'y 7.0

I'm sorry, but an uncaught exception occurred.

While running game code:
File "game/android.rpy", line 472, in <module>
File "game/android.rpy", line 197, in android_build
File "game/android.rpy", line 177, in update_android_json
Exception: build.google_play_salt must be exactly 20 bytes long.

-- Full Traceback ------------------------------------------------------------

Full traceback:
File "launcher/game/android.rpyc", line 472, in script
File "/Users/Hades/Desktop/renpy-7.0.0-sdk/renpy/ast.py", line 862, in execute
renpy.python.py_exec_bytecode(self.code.bytecode, self.hide, store=self.store)
File "/Users/Hades/Desktop/renpy-7.0.0-sdk/renpy/python.py", line 1912, in py_exec_bytecode
exec bytecode in globals, locals
File "game/android.rpy", line 472, in <module>
File "game/android.rpy", line 197, in android_build
File "game/android.rpy", line 177, in update_android_json
Exception: build.google_play_salt must be exactly 20 bytes long.