Dear @Nedivi
Were you able to change your trailer stability before when in TruckersMP before this situation happened?
Because normally the sliders go between 0 and 1 and I think there isn't anything that can be solved as what I heard from is the TruckersMP Dev haven't changed anything involving with the trailer stability.
Here are some topics that can help you out a bit as other people had this situation as well.
https://forum.truckersmp.com/index.php?/topic/76497-trailer-stability/
https://forum.truckersmp.com/index.php?/topic/74718-132-physics-warning/