Tenant can't be joined to the Tenant Broker, error 0x000000AD

Symptoms

Tenant can't be joined to the Tenant Broker, error 0x000000AD is thrown:

Cause

RAS Console on Tenant Connection Broker Agent can't connect to the Tenant Broker Connection Broker Agent over TCP port 20001

Resolution

Please allow connections over TCP port 20001 from RAS Console running on the Tenant to Tenant Broker CB.