Month to Month contracts.

[DIF]

I have started a season with a lower league Danish team. Most of them make amateur based contracts.
When I want to play a division game, hardly any of my players are allowed to play because of month to month contracts, whatever that means???

I didn't sign any of the players but after seeing this as a problem, I signed 6 players on amateur contracts and the same problem happens with them.
So basically I have 25 plays in my 1st and 2nd team that are not allowed to play. 
I can hardly set a team. 

Is that a bug or is there anything to do about it? Never experienced that in any earlier Football Manager games.

Any help is very appreciated.