Seems a memory leak. Check your EA.
TY for your response Alain. Check my EA for????? What specifically am I checking?
Your "black screen" seems to be caused by a lack of memory. As you said you are using an EA on a lot of charts, the most probable is your EA is using memory incorrectly. If you are using indicators they could also be the cause. Impossible to say more. So if you are a coder, check your code, if not, ask a specialist to do it for you.
You could eventually post your code here, but there is no guarantee you will get useful answer.