I have a Nexus 6 phone that I brought to T-Mobile service 9 months ago. Wifi calling has worked fine until recently. Now when I try to enable it, it will quickly switch back and forth between wifi calling and data several times then give me a message like, "Register with your carrier", "To make calls and send messages over Wi-Fi, first ask your carrier to set up this service. Then turn on Wi-Fi calling again from Settings." Everything has been set up and working for months. Any ideas?
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