A method performed by a communication server includes receiving a request from a first network entity to set up a communication session between a first user at a first device and a second user at a second device, wherein the first network entity is registered with the communication server, in response to the request, generating a token, wherein the token is configured to grant access to the communication session, sending the token to the first network entity, after sending the token to the first network entity, receiving the token from the first user at the first device, and causing the communication session to be set up between the first user at the first device and the second user at the second device according to the token.