Please check the following settings.
Let me tell you the simple steps i performed.
1. Defined Z business role by copying standard role IC_AGENT.
2. Open the Navigation bar profile which is assigned to the Z business role and maintain the position no as 21 for the Work centre id 'ISA-RTPCAT'.
3. Open the Z business role. Select the 'Adjust Work Centres' and uncheck the 'Inactive' option for the work centre id 'ISA-RTPCAT'.
4. Restart the Web UI and login into Z business role.
Regards,
Maddy