https://wccftech.com/microsoft-break-windows-7-update/

Some Windows 7 users are reporting problems with Windows Update seeing error 80248015. Several users have reported this issue on Microsoft’s forums and it appears the problem is probably being triggered by a file used by Windows Update that may have been set to expire on December 3 – yep, another date related issue. Since this file is expired, Windows Update fails to bring any new updates and shows up the following error message:

Windows could not search for new updates. An error occurred while checking for new updates for your computer. Error(s) found: Code 80248015. Windows Update encountered an unknown error.