Printix Client icon does not appear

The Printix Client icon does not appear. The PrintixClient-{user}.{number}.log file includes the following message:

System.NotSupportedException: The requested security protocol is not supported.
  at System.Net.ServicePointManager.ValidateSecurityProtocol(SecurityProtocolType value)
  at WindowsUI.PixWindowsClient.StartGUIWorkers()
  at WindowsUI.Program.Main(String[] args)

Resolution: Enable TLS 1.2.

Press Windows+R.

The Run dialog box appears.
Type regedit, then select OK.

Select Yes if prompted.

The Registry Editor appears.
Browse to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client.
Add the DWORD value name DisabledByDefault with a value of 0.
Restart the computer.