Unable to activate iPad Pro after reset (clear all data and content)

Hi guys, I am not able to activate my iPad after a reset. I have tried to restore and update the iPad via iTunes and OTA, under different wifi zone, including trying to restore using a different computer and also a different lightning cable. I am out of solutions.

I had even brought the set to the Apple Service Centre in my country. But they claimed that it was my hardware problem and wanted to charge me for a replacement fee. The set is already out of warranty.

The thing is my family had been using this iPad for the past two years without any issue. We had recently gave my mom an upgrade so I was trying to reset the iPad for my own use. Is anyone else facing the same problem as me?

When I tried to activate using iTunes, I got this error message, "The iPad "iPad" cannot be synced. Received an unexpected response from the device.

When I tried to activate via OTA, it says, "Your iPad could not be activated because the activation server cannot be reached. Try connecting your iPad to a Mac or to a PC with iTunes to activate it, or try again in a couple of minutes. If this problem persists, contact Apple Support at apple.com/uk/support"

Let me know if you guys have any solutions.