SIP Fax not registering

[IPhello]

I have a Lexmark XM3150 and I am trying to connect it to an IP500 9.0 and I keep getting the same error. Has anyone seen this?

15:41:30 694028215mS SIP Rx: UDP 192.168.10.173:5060 -> 192.168.10.3:5060
REGISTER sip:192.168.10.3 SIP/2.0
Route: <sip:192.168.10.3:5060;lr>
CSeq: 1 REGISTER
Via: SIP/2.0/UDP 192.168.10.173:5060;branch=z9hG4bKbc6a5138-d24a-e511-9986-0021b7613d0b;rport
User-Agent: T38Modem/3.12.1
From: <sip:VoIPFax@192.168.10.3>;tag=4a124e38-d24a-e511-9986-0021b7613d0b
Call-ID: bea84d38-d24a-e511-9986-0021b7613d0b@ET0021B7613D0B
Organization: Frolov,Holtschneider,Davidson
To: <sip:VoIPFax@192.168.10.3>
Contact: <sip:VoIPFax@192.168.10.173:5060>;q=1, <sip:VoIPFax@192.168.10.173:5060;transport=tcp>;q=0.500
Allow: INVITE,ACK,OPTIONS,BYE,CANCEL,SUBSCRIBE,NOTIFY,REFER,MESSAGE,INFO,PING,PRACK
Expires: 300
Content-Length: 0
Max-Forwards: 70

15:41:30 694028219mS SIP Tx: UDP 192.168.10.3:5060 -> 192.168.10.173:5060
SIP/2.0 403 Forbidden
Via: SIP/2.0/UDP 192.168.10.173:5060;branch=z9hG4bKbc6a5138-d24a-e511-9986-0021b7613d0b;rport
From: <sip:VoIPFax@192.168.10.3>;tag=4a124e38-d24a-e511-9986-0021b7613d0b
Call-ID: bea84d38-d24a-e511-9986-0021b7613d0b@ET0021B7613D0B
CSeq: 1 REGISTER
User-Agent: IP Office 9.0.3.0 build 941
Allow: INVITE,ACK,CANCEL,OPTIONS,BYE,REFER,NOTIFY,INFO,SUBSCRIBE,REGISTER,PUBLISH
Supported: timer
Server: IP Office 9.0.3.0 build 941
Reason: Q.850;cause=21;text="Call rejected"
To: <sip:VoIPFax@192.168.10.3>;tag=b576f3b0aac9feaf
Content-Length: 0

 

[intrigrant]

Sure, username/password incorrect.
Example:
In MANAGER:
System>LANx>VoIP>Enable SIP extensions
Licneses> Have a 3th party IP Endpoint license
User is named SIPFax, extn number = 500
Manager>user>Telephony>Logincode = 500
SIP Extension : telephonenumber = 500
Force Authorization = on

In SIP Fax
Mediaserver = IP Office ip address
Proxy = IP Office ip address
Username = 500
password = 500
Presentation name = 500 (IP Office does not show this name in calls so just set it to 500)

Make sure to have the codec and fax protocol are the same on both systems.

Then it should work, I have added many different SIP devices to IP Office and not one failed.