FM20 problem, can anyone help me?

I started FM up today and got a problem when wanting to start a new saves. When I start a new save I can't add certain leagues, it says there'e a requirement of maximum x amount of teams but there's more teams found (for example: Require maximum of 16 teams for next year's Jia League, found 17). Please help me. I've tried to Google but couldn't find anyone with the same problem, never had this problem before.

Screenshot example in down below.

Never mind, fixed it. It was a database that I added.

Generally any problem like this will be because of database files that are conflicting with each other, though @mons and @kingrobbo are much more knowledgeable than myself with these type of problems.

Glad its sorted.

As @VP. said and as you found out for yourself, it was an editor data file which you downloaded.

Whenever SI release a new database, i.e. usually around this time of the year, it may be the case that editor data files which were working fine previously now have some issues. This could be the case if a competition set-up has changed, some teams have disbanded, new ones have been added etc. This means that custom editor data files don't work and the game therefore does not allow you to choose those leagues.

Most custom file creators usually release new versions soon after to ensure compatibility, so it's worth looking at where you got any files you may have to see if they've been updated