User should not define functions with such specifiers, they are autogenerated by UHT. Definition should go into Func_Implementation.
Using UFUNCTION(Server, Reliable, WithValidation) with an RPC function results in a failed build in Visual Studio.
The same test in Main yields a different set of error messages.
The build fails with the following errors:
The build completes successfully.
Head over to the existing Questions & Answers thread and let us know what's up.