I would suggest looking at the log files after the error, since this is a generic error with no reason provided.
Will probably be in documents>SportsInteractive>Football Manager 2026>crash dumps.
If you can't work it out yourself, then you'd need to upload the information to somebody who can.
Mostly likely causes in my opinion however, since you're in a game:-
GPU driver issue
custom graphics/skins
Underpowered machine/throttled machine due to temperature
