dashboard frozen after 1 hour of flight

[french.aeroteam]

After 1 hour of flight, I was flying online and the controller contacted me to inform me that I had deviated from my trajectory. After checking, the autopilot via the FMC was no longer following the flight plan. In fact, I was about 50 Nm off my trajectory and it was impossible to interact to correct this. The exterior view and the scenery continued to function correctly. I could also change views, but I couldn't use the instrument panel and its features. I couldn't disconnect autopilot mode, and I couldn't switch to heading mode to correct the trajectory. I had to abort and stop my flight...