Hi, I have encountered a 403 error, "transient error", when trying to integrate a IP Gateway and an Exchange 2010 Unified Messaging server. The happens when IPgateway second time INVITEs UM according to the 302 redirect response from UM. Any advice/suggestion would be greatly appreciated and thanks in advance, Feng INVITE sip:+12407770000@10.2.66.193:5065;transport=Tcp SIP/2.0 Via:SIP/2.0/TCP 10.2.66.10;branch=z9hG4bKBroadWorks.2uhv-10.2.66.193V5065-0-478073984-692765293-1340985944318- From:"User2 fw"<sip:3018640002@unify.boston.local;user=phone>;tag=692765293-1340985944318- To:"Pilot UM"<sip:+12407770000@10.2.66.193> Call-ID:99120544318290612-518876376@10.2.66.10 CSeq:478073984 INVITE Contact:<sip:as.iop0.boston.local;transport=tcp> Diversion:"Feng Wei"<sip:2407770001@10.2.66.193>;reason=unconditional;counter=1 Allow:ACK,BYE,CANCEL,INVITE,OPTIONS,PRACK,REFER,NOTIFY,INFO Accept:application/dtmf,application/dtmf-relay,application/media_control+xml,application/sdp,multipart/mixed Supported: Max-Forwards:10 Content-Type:application/sdp Content-Length:280 (SDP Omitted) SIP/2.0 403 Forbidden FROM: "User2 fw"<sip:3018640002@unify.boston.local;user=phone>;tag=692765293-1340985944318- TO: Pilot UM<sip:+12407770000@10.2.66.193>;epid=3109CEB4CE;tag=1985494328 CSEQ: 478073984 INVITE CALL-ID: 99120544318290612-518876376@10.2.66.10 VIA: SIP/2.0/TCP 10.2.66.10;branch=z9hG4bKBroadWorks.2uhv-10.2.66.193V5065-0-478073984-692765293-1340985944318- CONTENT-LENGTH: 0 PRIORITY: Normal SUPPORTED: Replaces P-ASSERTED-IDENTITY: <sip:MSExchangeUM@SolutionsXchg1.broadworks.local> SERVER: RTCC/3.5.0.0 MSExchangeUM/14.01.0355.002 ms-diagnostics: 15604;source="SolutionsXchg1.broadworks.local";reason="Transient error."

Hi You can talk about UM on profession forum. http://social.technet.microsoft.com/Forums/en-US/exchangesvrunifiedmessaging/threadsTerence Yu TechNet Community Support