How to configure Polycom IP 331 with freePBX

General Help
1

I have purchased a Polycom SoundPoint IP 331. I cannot connet it to FreePBX server. When I dial from another phone to this phone, the error message is:
Service 423
Unavailable

Can an expert send me procedure of configuring IP 331 FreePBX?

Thank you!

2

http://www.voip-info.org/wiki/view/Polycom+Phones