Not able to add child pages

Hi,I’m using a Elbee Elgee 1.3.7 https://doasianfood.com. Somehow I can’t add a child pages under the parent page. I created a menu and created a new pages with parent page(e-shop) and click add but nothing show up. Please help me. I used another template before this one and I had no problem. I am new and Thank you for your help.