Can't speak while somebody's at the door

Hi all,

Hope somebody can help me out here.
My doorbell just works as a camera at this point. Because I can see the video’s and recording properly. Also notifications works okay, not all the time.
But the thing it’s supposed to do isn’t working. I can’t talk via the app as it’s keep on loading and after a while it disconnects. I’ve made a screenrecording to clarify: Google Drive video around 0.04 you can see me pushing the phone button and then the lags occur

My wifi is stable, have a mesh network and the router is located 1 meter from the doorbell.
The doorbell is connected to the power supply but has the same issuues when I use the battery only.

Really hope somebody can help because at this point it’s just another doorbell.

Thanks in advance.