While overseas iPhone requires re-activation, which sometimes works but more often does not. Initially it said my SIM card was not supported under the activation policy that assigned by the activation server.

kennypg wrote:

iphone 6

Network:Verizon

iOS 9.3.3

Twice now, once in Costa Rica in April and most recently in Ireland, while overseas phone warning reads:

"your iPhone could not be activated because the activation server cannot be reached. Try connecting your phone to iPhone to activate it, or try again in a couple of minutes. If the problem persists contact Apple Support at Apple.com/support."

or:

"The SIM card that you currently have installed in the phone is from a carrier that is not supported under the activation policy that is currently assigned by the activation server. This is not a hardware issue with the iPhone. Please insert another SIM card from a supported carrier or request this iPhone be unlocked by your carrier. Please contact Apple for more information."

My Carrier is Verizon and I replaced their SIM card upon my return from Costa Rica the end of April despite the fact the card is unlocked and good, in theory, for international travel,

Before activation the phone is locked and I can not access any applications like the camera, which, when I travel, I need more than the phone.

Apple says call Verizon. Verizon says, you guessed it, call Apple.

When I return to the States everything works fine. I thought the SIM card replacement would do the trick, so you can imagine my dismay when the activation warning came on after I took the phone off airplane mode after I landed in Dublin and the activation warning came on again.

What is going on?

I believe that is an issue with Verizon.

Our company is on AT&T - and our Attorney have travel all over the globe, Africa, London, South East Asia and they've never complained to me about that before.

It very well could be that when trying to activate the phone, you are in an area that is not covered by LTE, which then puts the device into CDMA mode. If you are not using Verizon's international roaming, you may not be connecting to their network, which in turn would not allow the device to activate. The SIM in a Verizon phone is only good for their LTE network, unless you are trying to use a local SIM. This could explain while you are able to use the device successfully when you return to the US, since you will be able to connect to the Verizon network.

You may need to contact Verizon about your setup while outside of the US, and what they have to say about activating your phone outside the US if you experience any problems. They should be able to answer that for you.