Cannot find either column “dbo”…or the name is ambiguous

"Cannot find either column "dbo" or the user-defined function or aggregate "dbo.fnycsoftware", or the name is ambiguous."

If you are absolutely sure that you do not have have another function with that name and the function is working fine, you might be getting this error because of a caching  issue with microsoft sql managemet studio.

FIX: Close Microsoft Management Studio and reopen the function.