Hi , i have the same problem but with CUCM 11.5 and CUACA 12.5.(1.6) . I Have a cluster with pub and sub and when pub is down , i have cti ports and cti rp registered to sub , but i cant login with attendant client . The user used for cuaca is an application user from cucm side and in tsp configuration i have cucm pub as cti server 1 and sub as cti server 2. In instalattion i setup CUACA with cucm pub ip address and aplication user that i refer earlier. Does anyone find out the solution? Should i do any upgrade to cucm , tsp or CUACA. Open a new case? Best Regards