Why can't I sell those players?

[Mokhtar Soliman]

I was trying to be sarcastic, I know that I should sell or sack players in order to sign the new comers. But I can't do it becaue they are not being sold. I keep putting them on market but no buyers yet.
I guess it is because I am on top of my server, but I did not choose to be there. Nordeus should put my players on other servers where there is players from levels higher than mine.