Can’t connect my phone to WiFi

Perhaps this article will help:

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

1st check if iPhone

WI-FI and router turn on.

• Go to Settings tap WLAN or Wi-Fi 
• Turn on Wi-Fi.

2nd reboot iPhone

In some cases, the

iPhone not connecting to the WI-FI problem can be easily fixed by restarting

iPhone.

• Press the power button 
• Swipe left of “side to the power of”
• Hold on your power button until you see the Apple logo

3rd turn off WI-FI

assist

If your iPhone

suddenly switches from to cellular, this will enable cellular automatically

when the WI-FI connection is weak.

• Go into setting
• Click on cellular
• Find WI-FI assist 
• Turn it off.

4th forget WI-FI

network

If your iPhone is not

connected to WI-FI network try using forget password

• Click on setting
• Tap on WI-FI/ WLAN option 
• Tap on the “I button” right next time to the name of
• your network.
• Tap on Forget this network
• Click forget in the pop-up window

Now back to WI-FI

connectivity and see if the error is fixed

5th

If none of those ways

worked then try giving a network rest

Go

to settings

Select general   

Scroll down and tap on reset

Select

the option to erase all the content and settings

Enter

your passcode

Tap on erase iPhone twice to confirm

hope it'd help you