Thanks for your idea Aleksej.

I've managed to resolve it myself. So for anyone else who finds the same situation here cause and the solution:

Cause: when you are using windows firewall, and try to create a QR code from within x5. It is blocked by windows firewall.

(In my case, when the warning below popped up on screen I must have missed it, so windows blocked it. and i did not know)

This is the windows message: "windows defender firwall has blocked some features of this app"

The Windows Firewall doesn’t ask you twice about the same application, but you can change the setting to allow or disallow any app in the future. To do so, head to Control Panel > System and Security > Windows Defender Firewall > Allow an app or feature through Windows Defender Firewall.

Click “Change Settings” to unlock the settings. Locate the application in the list, and then click the Public or Private checkboxes to control whether it’s allowed or disallowed, respectively.

If you uncheck both boxes next to an application, it won’t be allowed to connect on either Public or Private networks. If you check both boxes, the app can connect on both.

In my case, they were both ticked but it still did not allow the preview in x5.

Solution: delete the x5 entry.

FIXED.