Error 421 while connecting to Horizon via HTML Web Console after an upgrade to 2306 or Later

Hi, I experienced an issue where end users received an HTTP 421 error when connecting to a VMware Horizon web after it was upgraded to 2306. 

What is an HTTP 421 error?

The HTTP 421 Misdirected Request client error response code indicates that the request was directed to a server that is not able to produce a response. This might be possible if a connection is reused or if an alternative service is selected.


While connecting to Horizon over an HTML Web console, users encounter an error 421.


The default value of the security configuration setting allowUnexpectedHost has changed from true to false.

This means that connections using the name or IP address of a proxy, gateway, or load balancer that is not defined in will fail, even if checkOrigin and enableCORS are both set to false.


Add security configuration setting allowUnexpectedHost = true in your in connection servers after that restart Horizon services.

You can find from below address:

C:\Program Files\VMware\VMware View\Server\sslgateway\conf\

Finish 🙂

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