If it states that then it doesn’t appear as though it was answered in the eyes of Asterisk. You should provide a SIP trace using “sip set debug on” to show the actual signaling that happened.
If protocol debugging shows nothing, it means the device is dynamic and has failed to register, or it has failed a qualify, or it is not configured at all. A sufficient debug level should reveal which.
A call file HAS to dial something. You can use a Local channel to have it dial into the dialplan, where it could Answer/Wait/etc, and then send it elsewhere.