FYI, Normally a device needs to be activated (via website etc) with the target phone powered fully off.
Once the activation of the device is processed insert the sim card and power on the device.
This causes the iPhone to request an activation signal from the LTE towers. If an activation/provisioning was submitted by the carrier (within :30 min) the towers will respond with the provisioning signal and device programming. (this can take up to :15 min) Do not use the phone or otherwise interrupt the device programming.
I went through a similar issue with VMOBL a couple years ago when I was told to have the device powered on during the activation process.
Live and Learn..
I'm running into this same issue with a blank error message on the activate portion of the virgin mobile website when I enter the IMEI number. I am an existing customer swapping from an iphone 5S with an unresponsive screen to a new 5S that I received today. I tried both the IMEI from the phone settings and the one on the back of the box (only difference is a 0 added on the end in the phone settings) and have restarted my phone multiple times both with the SIM card removed and with it in.
I have already restored my new phone via itunes so I have everything from my existing phone, just need to get the service activated.
What's my next step to activating the phone? The blank error message on the website is quite confusing.