/mcpDefault value is 5090. Acceptable configurable range is 1024–49151. • SIP Mobile and Remote Access Port Default value is 5091. Acceptable configurable range is 1024–49151. Note Cisco Unified Communications Manager uses SIP Phone OAuth Port (5090) to listen for SIP line registration from Jabber on-premises devices over TLS. However, Unified CM uses SIP Mobile Remote Access Port (default 5091) to listen for SIP line registrations from Jabber over Expressway through mTLS. Both ports use the Cisco Tomcat certificate and Tomcat-trust for incoming TLS/mTLS connections. Make sure that your Tomcat-trust store is able to verify the Expressway-C certificate for SIP OAuth mode for Mobile and Remote Access to function accurately. You must perform extra steps to upload the Expressway-C certificate into the Tomcat-Trust certificate store of the Cisco Unified Communications Manager, when: • Expressway-C certificate and Cisco Tomcat certificate is not signed by the same CA certificate. • Unified CM Cisco Tomcat certificate is not CA signed. Step 5 Click Save. Step 6 Repeat this procedure for each server that uses SIP OAuth. Configure OAuth Connection to Expressway-C Use this procedure to add the Expressway-C connection to Cisco Unified Communications Manager Administration. You need this configuration for devices in Mobile and Remote Access mode with SIP OAuth. Procedure Step 1 From Cisco Unified CM Administration, choose Device > Expressway-C. Step 2 (Optional) In the Find and List Expressway-C window, click Find to verify X.509 Subject Name/Subject Alternate Name that is pushed from the Expressway-C to Unified Communications Manager. Note If required, you can modify the values. Alternatively, if the entries are missing, add Expressway-C information. If the Expressway-C has a different domain than the Unified Communications Manager, then the administrator needs to access the Cisco Unified CM Administration User Interface and add the domain to the Expressway C in the Unified CM configuration. Step 3 Click Add New. Step 4 Enter an IP Address, Hostname or fully qualified domain name for the Expressway-C. Step 5 Enter a Description. Step 6 Enter the X.509 Subject Name/Subject Alternate Name of the Expressway-C from the Expressway-C certificate. Feature Configuration Guide for Cisco Unified Communications Manager, Release 15 and SUs 800 Advanced Call Processing Configure OAuth Connection to Expressway-C