Wifi not working

Hi,

Try to run Apple Diagnostics if it reports about WiFi module error.

Use Apple Diagnostics to test your Mac – Apple Support (AU)

If it doesn't help, try to start up in safe mode and see WiFi is working or not.

Start up your Mac in safe mode – Apple Support (AU)

If it doesn't either, run Etrecheck and paste the result here.

https://etrecheck.com/en/index.html

Since Wi-Fi is provided by your modem, it is necessary to determine if the problem resides in the Mac's Wi-Fi connection or in the modem. First you want to make sure that the Wi-Fi is selected correctly in System Settings' Wi-Fi link. You can try resetting the modem by turning it off and then turning it on.