A similar issue might be caused by incorrect network settings. Manually and automatically changing network settings is possible. If you recently changed your iPhone's network settings and subsequently noticed that your device was losing signal, you've most likely made a mistake. You may restore the previous configuration by reverting the modifications you've made, but if that's not feasible, conduct a network settings reset instead. This will return your iPhone's network settings to their original or default settings. Here's how to reset your iPhone 8 Plus's network settings:

1. To access the Settings app, tap it.
2. Select General.
3. Reset may be found by scrolling down and tapping it.
4. Choose Reset network settings from the drop-down menu. This will restore your current network settings to their default setting.
5. If prompted, enter your device passcode to continue.
6. Tap to confirm network settings reset.

When the reset is complete, your iPhone will reboot automatically. Set up your wireless network at this point to restart Internet access on your iPhone.