I m not sure if this tip wil help you but i helped me. I have a problem with an error that 80% of the loading screens I disconect ppl sayd port forwarding dosent help so I dident do it and trayed a diffrent fix.And for some reason when i m in a skype call it goes down to 5-10% of the loading screens.It dosent matter if you are in a groupe call or alone with one guy or even the echo sound test if no one of your budys is alone it wil work the same.
I dont know why it works for me but i realy hope it wil work for your problems as well.
POSSIBLE FIX