Sadly I think the only solution is trying to sell the players again and again. If you can wait, you may until start of next season as it may be easier to sell players at that time.

As I understand, there is no max club level in T11. So some managers will be in highest level of their server. There are few or even no same level or higher level manager willing to buy the players in markets. This increases the difficulties in selling players at top of servers.

As Nordeus creates Norgen players to disturb the players (appearing players in non-existing teams), they may need to also buy real managers' players at top of servers to ensure movement in the player markets.

If T11 have a maximum level, managers whose clubs can promote will eventually reach this. They all then buy and sell the same pool of players and there may be no such problem.