I had this problem. I noticed on a lot of my Wi-Fi devices, they wouldn't work with my phone sometimes, and I've noticed at least 1 reason. May not work all the time. But starts working instantly once I change it. I have 2 routers in my house, 1 for the kids, 1 for everything else, I simply changed to my Wi-Fi signal from the one the kids use to the other one, I can make calls instantly, or print instantly, chrome cast instantly, just make sure your not a blocked router, I have nothing about making calls on my router I believe, but for whatever reason, if I simply change what Wi-Fi network I'm connected to, it works. Hope this helps. Thanks