Activation server

I still use our iPad 2 in addition to our newer one. I recently got a message:

”Your iPad could not be activated because the activation server cannot be reached. Try connecting your iPad to iTunes to activate it, or try again in a couple of minutes. If this problem persists, contact Apple Support.

• iPad is fully charged
• can connect to the internet
• cannot get to any other screen except the Home Screen, internet provider selector screen and the above one.
• tried “in a couple of minutes” to no avail.

How do I get into my iPad?

Thanks.