SIP485 Ambiguous Error with Exchange UM when using SIP Trunking How to use a main line phone number with extensions to avoid this. – the UC Guys
There is a well known issue when using an E.164 dialplan in Lync Server that includes the extension portion the dial string (such as +14165551212;ext=1000) and assigning that to an Exchange UM AutoAttendant. If you are using a provider that…

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