kennysleap Said:
"iPhone 16 Pro - wifi problems - apps and websites lagging.: [...]So basically it doesn't load the websites or apps while they're being open.[...]"
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Troubleshooting a Lagging, New iPhone:
A. Close All Apps:
Apps may be open that are stalled. So, save what need be, and then close all apps. Hold you finger down as you swipe up form the bottom-left corner of your screen. Then, close all of these open apps, by sweeping up quickly for all apps.
B. Perform a Force Restart:
Try Force Restarting your iPhone. Save any information that need be. Then perform the restart. See if you can then perform this. Go Here: Force Restart iPhone - Apple Support
C. Update your New iPhone:
Try updating it to that, seeing if that fixes this. Important: Be certain to create a backup of your iPhone prior to bring it in. That way, you can have something to restore your iPhone from, should anything go wrong after the update install.