Need to know more about how you have your Conductor and TelePresence Servers configured.
What software version is the Conductor and the TelePresence Servers?
What licensing mode do you have Conductor and the TelePresence Servers setup to use, screen licenses or multiparty? If using Conductor XC4.0 and TelePresence Server 4.2.
How many screen licenses and/or multiparty licenses do you have?
How do you have your bridge pools setup?