Loud feedback noise when answering via app

I have a ring intercom, connected properly via the app instructions to an Tegui Horizon 0E7020. I can open the door without any problems via the app but when I answer the door via app the outside com of the doorbell makes an insanely loud high pitched noise, likely feedback. I have been playing with the audio levels on the app but it makes no difference. This only happen using the app, the phone works fine.How can I avoid this?