Thank you for writing in about the issue you're running into with sending a Message Center message.
I see that you are with NBC Universal and as such are on our Essential plan. Customers on our Essential plan can take advantage of a variety of support resources, including email support. One of your colleagues has already submitted a ticket for this same issue, so I will copy you on that thread.
You should see a response from us shortly requesting more details so we can better troubleshoot this issue.
Urban Airship Technical Support