A. The endpoint does not have the proper port assignments configured for SIP signaling
B. The Cisco Expressway failed to bind to the LDAP server, which is where the lab local SIP domain is learned
C. The lab local SIP domain does not exist on the Cisco Expressway
D. The endpoint uses the TCP protocol and the Cisco Expressway is configured to allow only TLS for SIP registrations
E. The lab local SIP domain is not configured in the Cisco Expressway allow list for registration