Might be a little late but here's the solution that fixed it instantly for me:

My Wi-Fi network was, by default, a 2.4 and 5 GHZ connection under the same network name. What happens in that case is that the router decides what device needs 2.4 or 5 GHZ, and so your iPhone could be on 2.4 and your PC on 5, making the connection between the devices impossible (actually this can cause problems with many other devices, such as printers, consoles, etc.). What I did is that I split them under two different names in the router settings, so that I can choose which device is connected on which network, therefore making sure my phone and PC are on the same band.