For example :
If You want to access this url http://test.example.com.vn/everything : you will type url in Google Chrome like that: test.example.com.vn/everything but Chrome auto switch to https://test.example.com.vn/everything but your server didn't open port 443 for subdomain : test.example.com.vn so It will return :Failed .
To resolve this problem :
1. you go to : chrome://net-internals/#hsts
Note : you don't need to query subdomain: test.example.com.vn , only domain not subdomain .
3. Input domain example.com.vn into below box : "Delete domain security policies" then click to Delete ,Done !