The story I just realized there is a problem when websites that use HTTP / 2 when accessed through Google Chrome browser even failed. Though in other browsers like Mozilla Firefox and Microsoft Edge normal.

The following error message appears:
This site can’t be reached
The webpage at https://servernesia.com/ might be temporarily down or it may have moved permanently to a new web address.
ERR_SPDY_PROTOCOL_ERROR
From this description there seems to be a problem with the implementation of the HTTP / 2 protocol (SPDY or Speedy is the old name before it becomes standard).
The problem is, yesterday was all smooth. What I change is the security header on Nginx, so I automatically check it out. And finally it seems there is one header that is not compatible with HTTPS + HTTP2 served through Nginx:
add_header Referrer-Policy: unsafe-url;
It seems that special Referrer-Policy headers are temporarily not used first. Note, if you use HTTP / HTTPS all headers can be used normally. The only problem is if active use HTTP2 on Nginx.