https://community.cisco.com/t5/ip-telephony-and-phones/problems-with-ring-back-and-no-audio/m-p/4888691#M410935 <P>Hello,</P> <P>We are having an issue with only certain numbers.&nbsp; The number is dialed then you hear maybe half a ring then silence.&nbsp; The calls stays connected but no audio and I see sender packets going out but no receiver packets.&nbsp; the calls flow is as follows.&nbsp; I spoke to my SIP Provider and they told me it's an issue with how cisco treats the 183 with SDP followed by a 180 with SDP.&nbsp; I tried blocking the 183 with sdp present then absent and nothing is working.&nbsp; Any help would be appreciated.&nbsp; Thanks.</P> <P>Phone ==&gt; CUCM ==&gt;SIP==&gt;CUBE==&gt;PST SIP Trunk.</P> <P>I have attached part of my cube config and the debug logs</P> <P>&nbsp;</P> Thu, 20 Jul 2023 15:30:00 GMT Denis Morin 2023-07-20T15:30:00Z https://community.cisco.com/t5/ip-telephony-and-phones/problems-with-ring-back-and-no-audio/m-p/4888691#M410935 <P>Hello,</P> <P>We are having an issue with only certain numbers.&nbsp; The number is dialed then you hear maybe half a ring then silence.&nbsp; The calls stays connected but no audio and I see sender packets going out but no receiver packets.&nbsp; the calls flow is as follows.&nbsp; I spoke to my SIP Provider and they told me it's an issue with how cisco treats the 183 with SDP followed by a 180 with SDP.&nbsp; I tried blocking the 183 with sdp present then absent and nothing is working.&nbsp; Any help would be appreciated.&nbsp; Thanks.</P> <P>Phone ==&gt; CUCM ==&gt;SIP==&gt;CUBE==&gt;PST SIP Trunk.</P> <P>I have attached part of my cube config and the debug logs</P> <P>&nbsp;</P> Thu, 20 Jul 2023 15:30:00 GMT https://community.cisco.com/t5/ip-telephony-and-phones/problems-with-ring-back-and-no-audio/m-p/4888691#M410935 Denis Morin 2023-07-20T15:30:00Z