Connecting FaceTime Issues

Hi, I hope someone has an idea of what’s been happening...

Never had an issue before with FaceTime, but in the last month, there is nothing but an issue. I have fibre optics for internet and my download is over 250 and 220 for uploads..Everytime my mom and I try to connect I get my pic in corner but her video says connecting, and when it does it is black with no no audio either. Well try a couple of times and finally works. Now I was thinking it was on her end becasue I have such good internet, and she doesn’t but apparently she just had it checked and it doesn’t do it with anyone else...now it did do it with my sister and her, but since nothing, I’m the only one with a connecting issue. I need to say that I only use FaceTime with my mom..so I couldn’t tell you if it’s anyone else. But I can’t understand why is this all of a sudden. Yes I have restarted the app, unin the app..reinstalled and did go into settings and turn off in there as well. Please at a loss and this is just frustrating. Thank you, and Merry Ho Ho