If you play a league game which is not fully confirmed within the league schedule (i.e not a red box) you will not be able to submit a result - you also risk the whole thing being voided!!
Especially in private server games where there is no server booking to back up the fact a game was 'agreed' upon.
From the rules page:
Especially in private server games where there is no server booking to back up the fact a game was 'agreed' upon.
From the rules page:
Matches not submitted to the schedule may not be considered official league matches