You may see this when creating a picks & bans page. If you do, it applies to the game ABOVE the error. It means one of the following happened:
- You have one or more champions duplicated
- One or more champions are missing
This error does NOT check that all champions are correct or even valid; if you input Urf, you would not get a champion error. Please be careful and check your data entry!!
You can see a list of pages with champion errors here.