Hello,
Open Device Manager, right click your WiFi device/driver, and select Properties. Switch to Power Management tab, uncheck 'Allow the computer to turn off this device to save power' option.
If that doesn't works, try to perform Network Reset:
- Open Settings app, click Network & Internet > Status > Network reset link.
- Now click on Reset button on next screen.
- In confirmation prompt appearing next, click Yes.
Hope this helps!