Dex not working in s21 ultra

[Ratheesh0110]

Dex service not working, the samsung dex option in settings is also not opening.

When i press the Samsung Dex option nothing is happening.

Phone software is updated and also reset the phone. 

Any solution for this problem 

[traver]

Cable or wireless?

[Ratheesh0110]

Both

[Ratheesh0110]

When i press this option, nothing is showing

[Samsung_specialist]

Navigate to Software information.
Disconnect it from the monitor, and then navigate to and open Settings on your phone. Swipe to and tap About phone, and then tap Software information.

Verify phone configuration.
Swipe down. If "Knox Customization" appears, the device has been configured with Knox Customization Configurator, and you will need to proceed to the next step.

Download the Samsung DeX patch for your phone.
Use Internet or Chrome to navigate to the Knox website, and then tap Next. Tap Finish, and the phone will check for an update. Tap UPDATE.

[Ratheesh0110]

There is no Knox Customization

[Ratheesh0110]

How do i register the device