Expected close status, received none.
No close code frame has been received.
Server acting as gateway received an invalid response.
Endpoint is leaving (browser tab closing).
Client wanted an extension which server did 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 large frame.
Temporary server condition forced blocking the client's request.
Endpoint received an unsupported frame.
Endpoint received inconsistent message.