Plugin area and whole dashbord showing blank after update.

I am working with an 8-10-month-old plugin with lots of issues like the payment gateway disappearing after cancelling an order. Customers can’t pay from pending payment if payment failed for any issue.
Now, hope that fixed. but i can’t even check because after updating the bkash plugin Plugin area and whole dashboard show blank after the update.

Screenshoot

The page I need help with: [log in to see the link]