Why does my Wi-Fi say weak security?

horsply wrote:

Why does my Wi-Fi say weak security

This is NOT an iPhone problem; it is a problem with the settings on your Wi-Fi router.

A "Weak Security" notification means that your Wi-Fi router is not configured correctly. There is a new feature in iOS 14 and Mac OS Big Sur (11) and later versions that checks and displays a message if your router is not using the most up-to-date security settings. Note that your router has always had weak security, you just didn’t know about it until now. 

See this Apple support article for how to configure it correctly—>Recommended settings for Wi-Fi routers and access points - Apple Support, specifically the section headed Security. And don't forget to configure your range extenders (if any) also!

After you change the router settings you should Forget the network in your phone settings and reconnect.

Note also that weak security does not interfere with using Wi-Fi, it is just a warning. Your Wi-Fi should still work normally, and, if it doesn’t, it is not because of the weak security message.

horsply wrote:

How do I change the setting on the router

You will need the user guide for the router, which you can get from the manufacturer’s website, or from your ISP’s website if your ISP supplied the router.

because your wifi router is not using a very secure setting

Recommended settings for Wi-Fi routers and access points - Apple Support

you will need to get into the settings of your router. Maybe google the brand and model and see if you can find a user manual

How do I reset me router security?

Reas my post right above yours on this page.