https://business.forums.bt.com/t5/Archive/Unresolving-SIP-servers/m-p/16592#M21331 <P>Hi all,</P><P>&nbsp;</P><P>I know BT don't support third party products, but I thought I would ask the users of this forum for their advice.</P><P>&nbsp;</P><P>I am using 3CX as part of my phone system. For ages, the outgoing calls wouldn't resolve, bringing up a '480 Temporarily Unavailable' error. I couldn't work out why...</P><P>&nbsp;</P><P>However, I just changed my SIP address and outbound proxy address to an IP associated with&nbsp;the servers for the BT Broadband Talk - the home VoIP service (I presume). When I dial a number, I get the message "Sorry, you cannot make or receive calls on this line", etc etc. I am presuming from this that the line is connecting, but failing to authenticate properly, as I have&nbsp;a Broadband Business Voice account, and thus cannot use the home service..</P><P>&nbsp;</P><P>However, if I try to nslookup the server addresses I've been given for Broadband Business Voice, nothing can be detected.</P><P>&nbsp;</P><P>Am I therefore correct in thinking that this is an error on BT's end, and that the servers aren't registered properly for some reason?</P><P>&nbsp;</P><P>Many thanks for any suggestions, thoughts, or words of advice in advance!</P> Tue, 14 Sep 2010 15:54:56 GMT jennipinnock 2010-09-14T15:54:56Z https://business.forums.bt.com/t5/Archive/Unresolving-SIP-servers/m-p/16592#M21331 <P>Hi all,</P><P>&nbsp;</P><P>I know BT don't support third party products, but I thought I would ask the users of this forum for their advice.</P><P>&nbsp;</P><P>I am using 3CX as part of my phone system. For ages, the outgoing calls wouldn't resolve, bringing up a '480 Temporarily Unavailable' error. I couldn't work out why...</P><P>&nbsp;</P><P>However, I just changed my SIP address and outbound proxy address to an IP associated with&nbsp;the servers for the BT Broadband Talk - the home VoIP service (I presume). When I dial a number, I get the message "Sorry, you cannot make or receive calls on this line", etc etc. I am presuming from this that the line is connecting, but failing to authenticate properly, as I have&nbsp;a Broadband Business Voice account, and thus cannot use the home service..</P><P>&nbsp;</P><P>However, if I try to nslookup the server addresses I've been given for Broadband Business Voice, nothing can be detected.</P><P>&nbsp;</P><P>Am I therefore correct in thinking that this is an error on BT's end, and that the servers aren't registered properly for some reason?</P><P>&nbsp;</P><P>Many thanks for any suggestions, thoughts, or words of advice in advance!</P> Tue, 14 Sep 2010 15:54:56 GMT https://business.forums.bt.com/t5/Archive/Unresolving-SIP-servers/m-p/16592#M21331 jennipinnock 2010-09-14T15:54:56Z