There is an error when i make the update

that pop up is a bug that many users have been seeing. I thought there was a new beta version released yesterday, but I'm not sure. In any case, you'll have to wait it out until an update is available.

If it gets unbearable, you can always remove the beta software

How to uninstall iOS beta software - Apple Support

iOS 14.2 is a beta version.. we don't support beta software in these forums

removing the beta profile does not remove the beta software. read thru the entire link I provided if you are trying to remove the beta software