@RITAC 

Under Settings / WiFi find the network name you are referring too and click the   (i) to edit / open it

You should have a setting saying something like     PRIVATE ADDRESS     if selected, de-select this and try again

This came out in IOS14 and caused all sorts of issues by spoofing MAC addresses, home users on single AP or WPA2 PSK  generally didn't have issues but Omada / Uniquiti etc users did.

If its not that try disabling band steering if you have it enabled, IOS devices tend to not like it either! 

I loved Apple devices until about 3 years ago when I got handed MDM support for 20k of them..  Since then I wouldn't recommend them to anyone outside single user, home use.. they constantly cause issues..   /END RANT :)