Editor error message when creating a league

So I'm trying to create a league in the editor. When making it, I ran into no issues until I tried to load it up in game and it kept crashing. I go into the editor and run a test on my leagues and I'm confronted with this error message:

'20/6/2017 - Friendly date range for 2016 [League Name] (3/8/2016) doesnt match with start of season (13/8/2016)'

I have googled it and have not found any answers, nor can I find this supposed 'friendly date range.'
Can anyone help me here?

It is necessary that you modify either the beginning of the date of the league (03/08/16 in 13/08/16) or you modify the date of beginning of the competitions in the nation (13/08/16 in 03/08 / 13).
Indeed, the game tell you that you have planned a start of the championship outside the dates you have defined.