After update to wordpress 5.0.3, I can’t update any page

Hello,
I am facing some strange problem. After updating to wordpress 5.0.3, I can’t update any page but I posts are updating without any error. It keeps showing up updating failed. I installed classic editor but in it I am getting error 500 when I tried to update in it. my url is Post free classified ads | No login required | Without Registration

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