I have a newly installed NS700. I have DSP card and SIP licenses. I have successfully registered my IP phones. But I cannot get my KX-NT700 SIP Conference Phone to register.

I am aware that the IP phones are IP Proprietary and the KX-NT700 is SIP.

I will also mention I had to disable VLANs on my IP phones for them to register.

All of my ports are default on the NS700.
Under the Virtual Slot and then Sip CARD Property Slot (V-SIPEXT32), the Slot 6 / Port 1 is where I want it.
The Extension number is set.
The Password is set.
The Connection shows Fault.
This SIP Phone Type and Current Ip Address obviously are blank and 0.0.0.0 as it has not registered.

Under the Extension Menu > Wired Extensions > Extension Settings:
Extension Number Matches above, Shelf, Slot, Port matches above.
Port Type is SIP
Telephone Type is "No Connection"

On the NT700
It is on the local network and has registered on the network using DHCP
Operation Mode is IP-PBX
SIP Ext. # matches the PBX
Sip password matches (case sensitive) the PBX
SIP User Domain Name is the primary IP address of the PBX.
SIP proxy is 0.0.0.0
SIP Registrar is primary IP Address of PBX
SIP Port is default
RTP Ports are default
VLAN ID is default of 4095
VLAN Priority is default of 0

On the NT-700, I did change the two IPs from the PBX to the DSP card IP, rebooted and then changed back to Main PBX IP and rebooted, but that didn't work either.

NT700 Rebooted several times.

What am I missing?

You said you have VLANS. What subnet is the conference phone on, is it the same as the system

Is the sip extension on the system card set as panasonic only. I know its a panasonic device and should be ok, but no harm testing

Make sure password is not too simple like 1234 as it doesn’t like that

Best way to test is getting microsip app on your laptop with the same credentials and run wireshark to see what response its getting from the system, if any

I cannot make sense of it. Per OBT's direction, I downloaded teh MicroSIP application. I used all the information above that I was using on the conference phone. The MicroSIP immediately registered on the NS700. I deregistered MicroSIP on the PBX. I then went back to the conference phone and retyped everything, even though I had checked the values and there were no typos, and the Conference Phone Registered.

Conference Phone Setup:
Operation Mode = IP-PBX
SIP Ext. No. = Extension Number in PBX SIP Card
SIP Password = Password "Not 1234"
SIP User Domain Name = Main PBX IP Address
SIP Proxy Server IP Address = Main PBX IP Address
SIP Registrar IP Address = Main PBX IP Address

You don’t normally need the proxy server when it’s local but no harm it being there.

Sometimes it just helps to redo everything from scratch, the smallest thing like a space at the start or end of something can stop it working.