LEG. Campaign issue. Help??

Hello.
Started playing campaign on legendary. Got to the battle of sunaion today and started playing through with no issues. Got to the part where there are multiple AA cannons in the same area. I went down and my AI team quickly followed, resulting in a checkpoint restart. The issue is that instead of restarting the checkpoint, the game shutdown. I tried to reload a few times and the same thing happened. I restarted the level and went down in roughly the same place and the exact same happens.
Has this happened to anyone else? Anyone got any ideas?
Cheers

I’ve had a similar issue - Enemy Lines on legendary. Played with no problems up to just near end of level, died. Game will now not load checkpoint but shuts down to Xbox dashboard. No issues with MP.

Any ideas?

Thanks.

you have to restart the level