X-LITE Registration Error 403 - Forbidden

[RobiB]

1. Brekeke Product Name and version:
2.3.6.0/286

2. Java version:
1.5.0_10
3. OS type and the version:
Windows XP V5.1
4. UA (phone), gateway or other hardware/software involved:
SoftPhone X-LITE 3.0 build: 53117 and HardPhone ZULTYS ZIP4x5
5. Select your network pattern from http://www.brekeke-sip.com/bbs/network/networkpatterns.html :
1
6. Your problem:
Phones cannot register with SIP server. Server and phones are behind NAT. X-LITE is on same machine with SIP Server. I have more or less default settings of the SIP Server.
X-LITE responds with: "Registration Error 403 - Forbidden"
and hardphone (ZULTYS) tries but canot register on SIP server (phones send REGISTER requests). SIP server responds with:"401 Unouthorized" or "403 Forbidden".

[hope]

is the authentication for REGISTER AND INVITE set on at sip server side/ configuration/ SIP/ Authentication?

if yes, you can set them off and restart sip server or keep them on and create authentication for each registering user at sip server/ User Authentication, and put the same user name and password on the phone side/ user and authentication and password.

[RobiB]

Authentication for REGISTER AND INVITE was set to on.
I set it to off and now it works. Thank you.