fix: Forbidden instead of InvalidParam when joining

src/client_server/membership.rs

@@ -839,7 +839,7 @@ pub async fn invite_helper(
 
         if !auth_check {
             return Err(Error::BadRequest(
-                ErrorKind::InvalidParam,
+                ErrorKind::Forbidden,
                 "Event is not authorized.",
             ));
         }