You can check out Mendix's official documentation, it will be helpful.
f it is a microflow parameter you're passing of a particular type, send same type of object from the calling place.
MF - A(Expecting parameter P)
MF - B(calling MF A, but not passing parameter) could throw an error.
Same is applicable for NF or any function.
You could make the parameter as optional also which will solve the problem.
It would be easy if you share your error details.