How to test communication between UAG and CS

Many times I found myself having to demonstrate that the communication between the Unified Access Gateway and the Connection Servers was not working due to problems with poorly configured firewall rules. A very useful test is to connect to the UAG console and launch the classic CURL command:

curl -v -k https://<FQDN or IP ADDRESS CS>:443/

the outcome of which is as follows if the connection is ok (HTML output)

or the following if the connection is not enabled on the firewall

More info and tools here:

How to test communication between UAG and CS

421 Unknow

After upgrading Horizon to 2306 2212.1 or 2111.1 we see this message when trying to connect from UAG

In the log, I see this error:

2021-09-24T22:05:34.737-07:00 ERROR (1B08-1A58) <SimpleDeamonThread> [h] (ajp:admin:Request190) Unexpected Origin:

2021-09-24T22:05:34.738-07:00 DEBUG (1B08-1A58) <SimpleDeamonThread> [v] (ajp:admin:Request190) Response 404 Not Found [close]

The fast solution is to set allowUnexpectedHost to true on the file. This is located on each connection server in     c:\program files\vmware\VMware View\Server\sslgateway\conf. and restart the horizon connection services

Cross-Origin Resource Sharing (CORS) with Horizon 8 and loadbalanced HTML5 access. (85801) (

Error 421 while connecting to Horizon via HTML Web Console after an upgrade to 2306,2111.1 or Later (93915) (

421 Unknow