I have a problem with XCode running. It constantly cannot build while my code is good. Something with conversion is the problem but i cannot find it. Please help I cannot continue to work. Xcode was able to run before even with this error, but when I reopened the project, now I cannot run it at all. There is nothing red underlined in the code.

Xcode Error: Cannot convert return expression of type '()' to return type 'Message'

Files with Error.zip