Cloudflare received an unknown error from the origin server.
The origin server refused the connection from Cloudflare.
Cloudflare was able to connect to the origin server, but the server did not respond in time.
Cloudflare could not reach the origin server. This may be due to DNS or network issues.
A connection to the origin server was established, but it took too long to respond.
Cloudflare could not complete an SSL/TLS handshake with the origin server.
Cloudflare could not validate the SSL certificate on the origin server.
Cloudflare could not resolve the DNS for the origin server, or the origin is unreachable due to DNS issues.