Help! Ipad mini is offline, although online.

My internet connection stopped working a couple of days ago. I can‘t get access via wlan or mobile network, although both are connected. It logs onto my router and my network, but no data seems to go through.
I tried restarting the device to no avail. Now I can‘t reset the ipad, because it doesn‘t let me before doing a backup - wich obviously I can‘t.

Any ideas out there? I‘m not a noob and usually I find a way or workaround, but in this case I‘m drawing a blank. Any help would be massively appreciated.