I got a problem with signing new players. When I try to make an offer for most of the player there is a message at the bottom saying that I will not be able to register this player for the league until the next window. I play Southampton and bough 3 players without any issues nut now I have this problem. Also the message is not shown on some players like Saka from Arsenal but its still there for other Arsenal or English players. Is this supposed to be like that ? What rule is there ?