I've just brought an ipadmini I can't activate it, the message that comes up is the activation server can not be reached, I can't do it via iTunes as I don't have access to a desktop or laptop
see the "more like this" section on the right side of this page, or do a simple forum search, as your question has been asked and answerd many times.
I assume you have a valid SIM card for your cellular provider? In that case contact your cellular provider.
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