If this problem is still not resolved after installing the updated devices drivers, then it is recommended that you try another Adapter like Microsoft Wireless Display Adapter.

If Miracast fails to work, the first step you need to do is check if your device drivers are up to date, including all the displays and Wi-Fi drivers And make sure your PC supports the Wi-Fi directly.

Here are several suggestions that might help you. It is reported that some users encounter the problem “Miracast on Windows 10 not working” sometimes. What Can I Do If Miracast on Windows 10 Not Working Right now, you can press Win + P to configure both the Miracast on Windows and the display. After that, you can enable the Miracast on Windows 10 successfully. Then wait for the displays to appear in the list. Now select the Connected devices on the left tab and click on the Add a device on the right side. Inside the Settings window, navigate to the Device and double-click it. Right-click on the Start menu on the bottom left of your PC, and select Settings.

If not, you need to connect the external displayer with the HDMI port of the TV and power it on.

If your TV or projector comes with built-in Miracast support, just turn it on. Read More How to Enable and Use Miracast on Windows 10

Sony vaio miracast windows 10