Thank you ! That problem has solved by hosting provider.
So I have some else trouble :
1. I have some product want to relative with post but after set up custom content (Pic 1a) it now show any content below description (Pic 1b)
2. When I set instance “Related Products” then turn on “Show the plugin under content?”, “related product” and “may you like …” got too jumble (Pic 2) (Link: http://wowmart.vn/sp/thuoc-bo-danh-cho-phu-nu-tren-50-tuoi-one-a-day-womens-50-multivitamins-200-vien/)
Sorry for my bad English
Thank you !