Wireless router recommendations for wifi calling

I have an iPhone 6 and I'm living currently abroad in Ecuador. I have used the wifi calling feature in hotels and cafes without any problems. However, when I try to use wifi calling in my apartment, the wireless router crashes. All of my other devices work fine until I enable wifi calling on my iPhone. Is there a recommended router that I can purchase or should I upgrade the speed of my plan? I currently have 5 Mbps download speed using a Huawei Echolife HG8245 wireless router on a fiber optic network. Thanks!