Problem in connecting Wifi

Check the following Apple articles:

Connect to Wi-Fi on your iPhone, iPad, or iPod touch

Connect to Wi-Fi on your iPhone, iPad, or iPod touch - Apple Support

If your iPhone, iPad, or iPod touch won’t connect to a Wi-Fi network

If your iPhone or iPad won't connect to a Wi-Fi network - Apple Support

Check the route settings -> Recommended settings for Wi-Fi routers and access points

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

If you need help with your Wi‑Fi password

If you need help with your Wi‑Fi password – Apple Support (UK)

•  You need to sign in to your router.
• The Wi-Fi network name, or SSID (service set identifier), is the name your network that has a password.

or If you have iOS 16 / iPadOS 16:

Go to -> Settings -> tap Wi-Fi -> tap on the hidden Password -> enter Passcode -> you will then see the Wi-Fi Password.

If they are On, turn Off Hotspot & VPN.

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i am using iPhone SE 2nd generation

Update your iPhone to iOS 17.

This recomendation is useless for my iphone SE 2nd. It does not connect to 5ghz wifi networks. It used to, 2 years ago, but now it does not. I have allways updated iOS hopping it will fix it, but up to 17.5.1 it was not solved.