What's HTTP code zero means?

[favoyang]

I got messages with HTTP code 0 and response time 0.

[CN] Unity Registry /package-name (https://packages.unity.cn/com.unity.addressables) was down:

HTTP code: 0
Response time: 0 ms

The server is located in China, I expect the connection from the US to China can be bumpy. So what the messages mean?

• the URL is not reachable (TCP connection failed)
• or the request is timeout?

[AnandChowdhary]

You're right, this means that the URL is not reachable. If the response time and HTTP code are both 0, the connection couldn't be established.

Most likely, this is because that URL (which works perfectly fine for me) is not accessible to GitHub's IP address in the United States.

[favoyang]

Thank you.