It works on my home router, but when I go to any other area (say, my parents) that has no cell service, I cannot use calling over wifi.
Is there something I should be doing to use this in more than one location?
Best answer by Dinh
What is the internet provider at other places?.
There were some issue with DNS server with several ISP. You need to change the DNS server on the phone (or the router. Koodo didn't have a detail instruction on it but Telus have. You could check it here, it is similar https://www.telus.com/en/bc/support/article/wifi-calling-faq
I would try to reset the network settings of the phone and reconnect the phone the wifi network again. After that, you could turn on Airplane mode with Wi-fi ON, hopefully it will connect. Carriers don't restrict wificalling based on their location, it could be issues with settings somewhere.