facetime not working on my iphone 8 plus

every time i facetime someone i will be able to talk to them for up to 10 seconds but not see them. then poor connection will come up even tho we both have full bars. it will then end my call and say facetime failed. this happens at the exact same time every time and it only happens on my iphone 8 plus. i’ve reset my facetime but still get the same results. absolute ********!!!😡