A customer reports that outbound calls from Cisco UCM to Cisco Unified Border Element are not getting early media. During troubleshooting, the customer finds that Cisco UCM is sending a delayed offer SIP INVITE. Cisco Unified Border Element responds with a 183 Session Progress with SDP message. However, the customer finds that Cisco UCM does not respond to the 183 messages. Which action must the customer perform to resolve the problem?