66   Installation troubleshooting (optional)
598 Network read 
time out error
This status code is not specified in any 
RFCs, but is used by Microsoft HTTP 
proxies to signal a network read timeout 
behind the proxy to a client (NETA-21) 
in front of the proxy.
Contact customer’s network/system 
administrator.
599 Network connect 
time out error
This status code is not specified in any 
RFCs, but is used by Microsoft HTTP 
proxies to signal a network connect tim-
eout behind the proxy to a client (NETA-
21) in front of the proxy
520 Origin Error This status code is not specified in any 
RFCs, but is used by Cloudflare's 
reverse proxies to signal an “unknown 
connection issue between Cloud Flare 
and the origin web server” to a client in 
front of the proxy. So customer who has 
Cloudflare proxy for their network get 
this error
522 Connection 
timed out
This status code is not specified in any 
RFCs, but is used by Cloudflare's 
reverse proxies to signal that a server 
connection timed out
523 Proxy Declined 
Request
This status code is not specified in any 
RFCs, but is used by Cloudflare's 
reverse proxies to signal a resource 
that has been blocked by the adminis-
trator
524 A time out 
occurred
This status code is not specified in any 
RFCs, but is used by Cloudflare's 
reverse proxies to signal a network read 
timeout behind the proxy to NETA-21 in 
front of the proxy.
Error code Root cause Solution