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phone doesn't ring on Inbound call (intermitent)

Occasional Visitor

phone doesn't ring on Inbound call (intermitent)


I have a polycom SoundPoint IP 550. Current software version :

I use it with a (fongo) I configured the phone sip and other configurations with the web interface of the phone. I always can make outbound call. But I got problem with inbound call. At first inbound call it work well and the phone ring. If I called my phone (with my cellular for example) the second time the phone doesn’t ring and the call is going to the message box. Than if I change RTP setting enables to disable or vice versa and reboot the phone the phone ring on the first next inbound call. Then the problem comes again. If I only rebbot the phone without changing RTP setting to enable or disable the problem persit.

That behaviour occurs even if I connect the phone directly on Internet zone without firewall.

I try a third party soft phone on my computer and selected the I did not experience any problem with the same sip provider.


Thank you



Polycom Employee & Community Manager

Re: phone doesn't ring on Inbound call (intermitent)

Hello valiquettep,

welcome to the Polycom Community.

It is always useful to include the currently used SIP or UC Software version as issues experienced may already be addressed in a newer release.

This also allows yourself and others to check against current software release notes.

The above is also stated in the "Read First: Welcome to the Polycom VoIP Forum"

Therefore the Polycom VoIP FAQ contains this post here:

Question: How can I find out my SIP UC Software Version or the BootROM Version of my Phone?
Resolution: Please check here


In addition it would be of interest who advised you on the configuration that you are currently using as this is quite complex and may be the root cause of your issue.


I would suggest you factory reset the unit and simply follow this post here:


Oct 7, 2011 Question: Can I register or is my Polycom Phone compatible with a “XYZ” SIP Server?

Resolution: Please check => here <=


The next step would be to work with your Service provider to troubleshoot this or follow this FAQ post here:


Jan 19, 2012 Question: How to troubleshoot Polycom VoIP related Issues?

Resolution: Please check => here <=


The above should show the INVITE arriving at the phone.

Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.

Best Regards

Steffen Baier

Polycom Global Services

The title Poly Employee & Community Manager is a community setting and does not reflect my role. I am just a simple volunteer in the community like everybody else. All posts and words are my own & do not represent the views of Employer.


Notice: This community forum is not an official Poly support resource, thus responses from Poly employees, partners, and customers alike are best-effort in attempts to share learned knowledge. If you need immediate and/or official assistance please open a service ticket through your proper support channels.
Please also ensure you always check the VoIP , Video Endpoint , Skype for Business , PSTN or RPM FAQ's
Message 2 of 4
Occasional Visitor

Re: phone doesn't ring on Inbound call (intermitent)

Hi Steffen,


Sorry for the late reply.


I followed your advice and everything is working well now.


Thank you very much.


Best Regards



Message 3 of 4
Occasional Contributor

Re: phone doesn't ring on Inbound call (intermitent)

What was the fix?

Message 4 of 4