I’ve given son my old MacBook Pro Retina (early 2015). Wiped the MacBook clean on disk utility and reloaded the OS. Set up as a new MacBook, gone to safari and most of the web pages aren’t loading properly, or at all. Trying to sign into iCloud and it’s telling me the details are incorrect (when I know that they’re not) I wonder if this is linked? Any advice is appreciated.
Earlier Mac models
Yosemite's Safari version is quite old and is unlikely to work with most recent websites. Update that Mac to a later macOS version and your troubles are over.
Update macOS on Mac - Apple Support
That model MacBook Pro can run Monterey. Nearly all (if not all) websites will load just fine.
You may need to upgrade in stages – e.g., by using a modern Mac or PC to download the .DMG file containing the Sierra installer to a USB drive, for transfer to the old Mac. Once the Mac is running Sierra, that might make it a bit better able to access Apple Support articles, and App Store links for more recent versions of macOS, itself.
Web pages not loading on Yosemite 10.10.5 on a rebooted macbook pro 2015
