QMC fails to load after enabling Extended Security Environment in virtual proxy

Extended security environment when enabled in virtual proxy sends additional information viz. OS, device, browser, and IP in the security header. Depending on the .NET version in the machine, the IP address may not be parsed correctly. As a valid IP information is not available, the user may not be allowed access to QMC. From another machine which has an IPv4 address, this may work perfectly.

Replication Steps:

1. Navigate to QMC->Virtual Proxies. Enable the option 'Extended security environment'.
2. As changes are made to proxy configuration, the QMC refreshes. After refreshing, the QMC may not load.
3. The repository security logs (C:\ProgramData\Qlik\Sense\Log\Repository\Trace\<server>_Security_Repository) will show entries as "'Unanticipated exception    Specified argument was out of the range of valid values.↵↓Parameter name: newAddress       at System.Net.IPAddress.MapToIPv4()'"
4. If the QMC is accessed from another machine with an IPv4 address or .NET version 4.6.1 or later, we may succeed.

Extended security environment when enabled sends additional information viz. OS, device, browser, and IP in the security header. If the machine IP is an IPv6 address, and the .NET version in the machine is older than 4.6.1, it will throw this exception "Unanticipated exception    Specified argument was out of the range of valid values. Parameter name: newAddress at System.Net.IPAddress.MapToIPv4()". This is because of parsing issues while converting an IPv6 address to IPv4. As a valid IP information is not available, the user is not allowed access to QMC.

This issue is fixed in Microsoft .NET Framework 4.6.1. Upgrade to this version or later to fix this.