Expected close status, received none.
No close code frame has been received.
Server acting as gateway received an invalid response.
Endpoint left (browser tab closing).
Client wanted an extension which server does not negotiate.
Normal connection closure.
Received message violates endpoint policy.
Endpoint received a malformed frame.
Internal server error while operating.
Server/service is restarting.
Failed to perform a TLS handshake.
Too big frame.
Temporary server condition forced blocking the client's request.
Endpoint received an unsupported frame.
Endpoint received inconsistent message.