Posted in Lync Server 2010, Lync Server 2013, Polycom, Skype for Business

Polycom PIN Authentication Not Working

When you are sure and confident that you have already configured DHCP server to support Lync phones however PIN authentication still not working with Polycom CX and VVX series, try to check the version of your NTP servers in the environment.

I had an issue before that AudioCodes 4xxHD phones are surprisingly working with PIN auth while Polycom CX and VVX weren’t.

Wireshark Trace from NTP version 3.NTPv3

With all the NTP servers listed, all of them replied version 3 only. And from the packet, it seems the clock is not synced.

Wireshark Trace from NTP version 4

NTPv4One NTP server is on version 4 and from the packet, clock has no warning.


By standard, NTP version 4 should be compatible with version 3, but for some reasons version 3 does not works well on Polycom phone. So ask your customer to setup a new NTPv4 to support your VVX or CX phones and add it to your DHCP configuration. PIN authentication should work after that.



Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s