Windows remembers WI-FI connections so you don't always have to fill in your password. Sometimes however, the remembered hotspot is no longer up to date with the hotspot your iPhone is sending out. To fix this, please follow these steps:
- When you see the 'Can't connect to this network' error, right mouse click on the 'iPhone' connection and choose 'Forget'
- Wait for the list to refresh and connect to the iPhone hotspot again
- Use these steps to connect and/or change the password of your personal iPhone hotspot