A collaboration engineer is troubleshooting MWI issues with Cisco Unity Connection and Cisco UCM. Users report that MWI lights do not work when a new message is received. After doing a packet…

Question

Options

• AConfigure the SIP server list on the Cisco Unity Connection port group to match the Cisco UCM
• BAssign the proper voicemail profile to the directory numbers on Cisco UCM.
• CUncheck "Send Message Counts" on the phone system settings on Cisco Unity Connection.
• DUncheck "Accept unsolicited notifications" on the SIP trunk security profile.

• A
  7% (4)
• B
  10% (6)
• C
  82% (50)
• D
  2% (1)

Explanation

A SIP 503 Service Unavailable response from Cisco UCM in reply to a SIP NOTIFY for MWI often occurs when the body of the NOTIFY message contains information that UCM cannot process or is not configured to accept. When 'Send Message Counts' is enabled on the Cisco Unity Connection phone system settings, CUC includes voice message count data in the SIP NOTIFY body. Some UCM configurations reject this format, returning a 503. Unchecking 'Send Message Counts' causes Unity Connection to send a simpler SIP NOTIFY without the message count payload, which UCM can accept and act upon to illuminate the MWI lamp. The other options address different failure scenarios: the SIP server list mismatch would cause connection failures, voicemail profile is relevant to inbound voicemail routing, and unchecking 'Accept unsolicited notifications' would make the problem worse by causing UCM to reject all unsolicited SIP NOTIFYs.

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