ERR_INVALID_RESPONSE - This site can’t be reached. What is this?

[tomboi]

Hi,

I see this error

This site can’t be reached. The web page at https://1.2.3.4/ (IP address) might be temporarily down or it may have moved permanently to a new web address.
ERR_INVALID_RESPONSE

If I run curl command it says

HTTP/2 444
What is HTTP/2 444 error code? Is this normal?

[nixcraft]

It is a HTTP status code. Typically created by Nginx web server. It instruct nginx (or any other web server) to close the connection without sending a response to the client (in this case Firefox or Chrome or curl command), most commonly used to deny malicious or malformed requests access. There is nothing you can do. This is controlled by server. The best you can do is contact website operator and let them know about it. For example

curl -k -I https://192.168.2.254

Here is what it said:

HTTP/2 444 
server: nginx
date: Tue, 30 Jun 2020 13:36:27 GMT
content-type: application/octet-stream
content-length: 42

OR when I skip the -I option:

curl -k https://192.168.2.254

ERROR - CONNECTION CLOSED WITHOUT RESPONSE

Source:

• https://nginx.org/en/docs/http/ngx_http_rewrite_module.html#return
• https://en.wikipedia.org/wiki/List_of_HTTP_status_codes#444