Join live streaming as a co-host using agora_rtc_engine in flutter

I am building a live streaming flutter application. I have implemented live streaming and live comments (using pusher). When a viewer from the audience sends a request to join the live stream as a co-host, the main host accepts the request and the viewer navigates to the live streaming page again with a role of Broadcaster with the same Channel Name as before but instead of showing 2 camera frames, one of the main host and the other of the newly joined co-host it shows a black screen and throws and exception Unhandled Exception: PlatformException(-7, , null, null). I have also searched this exception, it says your SDK is not initialized properly but I have initialized it properly. I don't know where I am wrong. My question is how can I implement the multiple host functionality in a flutter app using agora. I have also read the agora documentation but unable to fix the issue. Any help will be appreciated. THANKS