iPad 3 shows "hello" screen after restarting device

After deciding to restart my iPad it gives me a "hello" screen, as if it was put into factory settings or I had updated the iOS. I had not done neither of the two (The iPad has already been updated to the latest iOS compatible with it a long time ago anyway - iOS 9.3.5 it should be) . I had merely switched my iPad off and on again before receiving the "hello" screen.

It then prompted me to activate the iPad. It then gave me the message "Your iPad could not be activated because the activation server is temporarily unavailable. Try connecting your iPad to iTunes to activated it or try again in couple of minutes." I tried again with no luck. I then followed instructions on this article (https://www.macworld.co.uk/how-to/ipad/how-activate-old-ipad-after-update-3638936/). I connected my iPad to iTunes (Version 12.6.2.20 - the latest version available on my laptop's OS X) on my Late 2011 macbook pro (OS X 10.9.5 - I do not think updating my OS X is the core of this issue) in order to back-up the iPad before attempting to restore it. However, iTunes gave me an unknown error message (error 0x8000015).

I have a back-up on iTunes for my iPad, but it was from a year ago. Is all my content still on my iPad, given the state that it is currently in? Is there anyway to recover the contents of the iPad without putting it in factory settings and restoring it from an old back-up?

P.S. There have been recent cases of hacking of (so-far) android devices and google accounts in the apartment block I live in and the hacker is suspected of being very close by. Is it possible for hackers to reset devices like this? Anyone know much about it/have experience in this regard? Just a thought at the back of my mind.