To fix a phone that keeps restarting when connected to Wi-Fi, try the following steps:

1. Restart your phone.
2. Check the settings for Wi-Fi connections and make sure you are connected to the correct network.
3. Check if the router is working properly.
4. Switch off your smartphone and the router, wait a few minutes, and then turn on both again.
5. Reboot your smartphone.
6. Check your smartphone for any available updates and install them.
7. Reset network settings.
8. Check for any faulty apps that may be interfering with your connection