iPad 2 not activating after iOS 8.4 restore

Hi,

yesterday I updated my iPad 2 to iOS 8.4, previous version on it was iOS 8.3, and everything went ok. This morning I got a message saying that it couldn't use cellular data and that I needed to restore it.

I did all the process: backing up my iPad 2, downloading iOS and installing it from iTunes with the restore option. Everything ok again, until iOS was restored.

Now my iPad starts the process, but when it gets to the activation screen, it takes a while looking to be activated and after several minutes, a message saying the activation servers are down and that I should try in a while.

I have tried to activate it from 2 different macs, with 2 different wi-fi networks and still have the same problem.

Does anyone have the same problem? Does anyone have any idea on how to fix this?

Many thanks,

Josep