Connected on Mac but no sounds on both studio and performer side

Hi;
My son connected via VST Connect Performer on his Mac Mini to record a song while his usic director was signing in from his home.
(which is set up with Razer Seiren X Microphone and the headset is connected).

We found our contact on the studio side and selected him. He came on the VST Connect Performer Video screen.
We were also able to hear our own voice on the headset and see the bars move on the screen.

but

We could not hear him or the music he was playing
He could not hear us.

It seems that a simple adjustment should fix it but we are first time users. Can you help please?

Our user name: alicemesenler (VST Connect Performer)
Studio user name: selimatakan (Cubase)

First step is to create an empty Cubase song, then apply “Create VST Connect” from the VST Connect menu. That should always work.
With an existing project try “Repair VST Connect”.
Open the Control Room window and check the “VST Connect Monitor” item. It should be located below the output you use, so if you use dedicated headphone outputs move it there. You should now hear the Performer in Cubase provided the Monitor control in the plugin is up which it is by default. The Performer signal goes directly to that output.
When Performer doesn’t hear you make sure your Talkback Mic is active in the Control Room and that it is enabled for the VST Connect Cue. You should see your talking in the Performer Monitor Mixer. If you do and Performer still doesn’t hear you make sure the Performer Master fader is assigned to the Performers’ hardware output (top item on the channel view).
For even more in-depth and troubleshooting see https://connectvst.com