If you are visiting a website and e

If you are visiting a website and experience this error, please contact the website owner or webmaster.

Are you the website owner?

A 522 error response is returned when CloudFlare could not establish a TCP connection to the website’s origin server.

This issue may occur if any one of the following conditions is true:

Rate limiting incoming connections from CloudFlare's IPs.
A process on the webserver is consuming all of one or more resources at the origin.
The domain is on a shared hosting platform where traffic or tasks for a separate domain on the same server is taking up one or more resources.
Network connectivity issues between CloudFlare and the origin web server.
While the above reasons are the most common, they are not the only reasons why a 522 might be returned when attempting to access your domain.

The TCP Handshake

When someone visits a CloudFlare-enabled website, a connection is established between CloudFlare and the website's origin server. To establish a connection, TCP uses a three-way handshake.

SYN: CloudFlare sends three SYN packets to the origin server.
SYN+ACK: In response, the origin server replies with a SYN+ACK.
ACK: Finally, CloudFlare sends an ACK back to the origin server.
At this point, both CloudFlare and the origin server have received an acknowledgement of the connection and communication is established. If the origin server does not send a SYN+ACK back to CloudFlare within 15 seconds, a 522 error will occur and the connection is closed.

Here is a diagram illustrating a successful TCP handshake:

Kết quả (Anh) 1:

If you are visiting a website and experience this error, please contact the website owner or webmaster.Are you the owner of the website?A 522 error response is returned when CloudFlare could not establish a TCP connection to the website's origin server.This issue may occur if any one of the following conditions is true:Rate limiting incoming connections from IPs CloudFlare's.A process on the webserver is time-consuming all of one or more resources at the origin.The domain is on a shared hosting platform where traffic or tasks for a separate domain on the same server is taking up one or more resources.Network connectivity issues between CloudFlare and the origin web server.While the above reasons are the most common, they are not the only reasons why a 522 might be returned when attempting to access your domain.The TCP HandshakeWhen someone visits a website,-enabled CloudFlare a connection is established between CloudFlare and the website's origin server. To establish a connection, TCP uses a three-way handshake.SYN: CloudFlare sends three SYN packets to the origin server.SYN + ACK: In response, the origin server replies with a SYN + ACK.ACK: Finally, the CloudFlare sends an ACK back to the origin server.At this point, both CloudFlare and the origin server have received an acknowledgement of the connection and communication is established. If the origin server does not send a SYN + ACK back to CloudFlare within 15 seconds, a 522 error will occur and the connection is closed.Here is a diagram illustrating a successful TCP handshake: