Aircraft suddenly falling through ground?

[Carson_Jones]

Can someone please explain what this is, I have had this issue before, around a year ago, and today, when attempting a flight from EGCC - LXGB, my “Tui Boeing 737-800” decided to fall through the ground when taxiing to Runway 23R at Manchester??? It refused to move and I also tried full power and pushback which did not do anything, please help?   

[Jet_Airways_995]

These steps from the user guide may be helpful :)

[Carson_Jones]

Thank you, I will give this try 👍🏼😊