The video stopped


First Sorry for my english…but i need help

I use Cubase during my live set.
Audio track for The Wav ( and clic )
Video track send to a 2 nd screen behind me

Since few days The video stopped / crashed but only The image, The sound is ok.
When it happens, i have to close and re-open cubase.

It’s impossible because all my live set is synchronise in one session so The show has to stop !

Is anyone has an awswer ?