Lack of managerial discipline??

I have no idea what it means and how to fix this with the players...advise???

Did you not warn/fine a player when he got a red card? If you don't punish players for getting send off the rest of the squad can get worried you don't have a very good descipline outlook.

If one of your players has a game with a rating below 6.0, you can either warn him or fine him for poor performance, if you don’t do so after a few games, some other players might think you’re a bit too relax with discipline. The same with booked players or sent off, you need at least to warn them when this happens. If you want to discipline a player, right click on his name, choose “speak about the player” (or something like that) then discipline player, “Warn”. Know that this can cause other troubles with the players you warn, they may want to move elsewhere.