Facetime Issues

Me and my long distance girlfriend are trying to FaceTime computer-to-computer and for some reason whenever I send her a request she only gets it on her phone and vice-versa. Everything in preference's is selected and when I called a woman from Apple even she herself said that everything seems to be right. She wasn't the most helpful representative as she had to ask someone else for tips. I have tried logging in and out and I am just trying to find a solution for this problem. I have been able to receive calls on my computer in the past, just not recently. Any advice or tips would be appreciated! Thanks in advance!