According to this thread on Microsoft Answers, after updating to latest version of WiFi Drivers “Marvell Semiconductor, Inc. – Net – 15.68.17013.110, the latest driver which was rolled out by the company in August. After updating to the latest version, users are only able to connect to 2.4 GHz WiFi connection and receive the error message “Unable to connect to this network” when trying to connect to 5GHz WiFi connection. Uninstalling and reinstalling the driver temporarily let users connect to 5GHz WiFi connection, but after installing the latest drivers issue comeback.

Fix – Unable to Connect to Wi-Fi in Surface Device due to Marvell Semiconductor

Specifically, the problem that makes it impossible to connect to the Wi-Fi network is due to the Marvell driver update to version 15.68.17013.110 released with the latest firmware on August 2, on Surface Pro 5 and 6, Surface laptop 1 and 2, and Surface Book 2.  At the moment there is no official solution released by Microsoft, but there’s a temporary solution which you can use fix the issue:

  1. Right-click on the Start button and select Device Manager from WINX menu.
  2. Go to the Network Cards tab and click on the arrow icon to expand the options.
  3. Double click on the Install Marvell Avastar Wireless-AC Network Controller.
  4. In the Properties window, switch to the Driver tab and then click on the Roll back driver. Once the old version of the driver is restored, the Wi-Fi connection should start working correctly. You can try this workaround unless the company releases the latest driver with a fix. Are unable to connect to WiFi Connection on your Surface device? Did you manage to solve the problem using the workaround discussed in this blog post? Let us know in the comments. Via – WindowsBlogItalia
Fix    Unable to connect to this network  Issue in Surface Devices - 55