Unable to check for a software update

I set my date and time manually and iinstalled the profile and then I restarted my ipad, but after that, when i when to the software update, it says unable to check for an update so does anybody know the solution

Set date and time manually on your device only helps you install the OTA Block profile.
Apple is not currently releasing any iOS 16 beta updates, so you don’t need to try to install them.