ERR_HTTP2_INADEQUATE_TRANSPORT_SECURITY Error When Accessing the Kiwi Syslog NG Web Interface

Kiwi Syslog NG uses HTTP/2 as its default transport protocol for the web interface. When accessing the web page, users may encounter the following error if the environment is configured to use HTTP/1.1 instead of HTTP/2:

This error indicates a transport protocol mismatch between the browser or system environment and the Kiwi Syslog NG web service. 
Because HTTP/2 is required, environments that default to HTTP/1.1 can cause a security conflict, preventing successful access to the Kiwi Syslog NG web interface. 

This issue occurs because the KiwiSyslog NG Server is advertising both HTTP/2 and HTTP/1, but having compatible issues exists with HTTP/2 failback to HTTP/1 did not work properly.

To resolve this issue, please upgrade to KSS NG 1.5 and above as improvement and change for compatible scenarios with HTTP/1.  If upgrade is not possible, use the workaround below:

1. Stop the KSS NG service from Services.msc
2. Go to "C:\Program Files (x86)\SolarWinds\Kiwi Syslog Server NG" and look for appsettings.json.
3. Create a backup of this file to a different location.
4. Edit the original appsettings.json and apply the following changes:
   • 

   • "AllowedHosts": "*",
     "Kestrel":{
     "EndpointDefaults": {
     "Protocols":"Http1"
     }
     ",
     "https_port": 5000

5. Start the KSS NG service.
6. Clear browser cache and cookies. Ensure you use the latest version of your browser.