why is facetime randomly ending by itself

im on an ipad, i’m on the latest ios version, and my model is iPad 8th Generation.

whenever i’m on facetime with anybody at random times it will end and say “FaceTime Failed” when nobody hung up!! this glitch is very annoying. but then like 15 seconds later i can call them back, then it ends AGAIN. this happens with every contact. i’m not sure if it’s my location or if it’s Apple. please help :(