I am trying to set up Wifi Calling as well. It seems to diasbled/deactivated (no option visible in settings). I tried to set up the E911 address (per T-Mobile website), but it didn't help. I had Wifi Calling on previous phone (the same SIM card). I have also other SIM card (foreign operator) that works in the roaming - same thing, worked fine on previous dual sim phone, but not on ZF9.
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T-Mobile website says otherwise:
Set up Wi-Fi Calling
To use T-Mobile Wi-Fi Calling, you need:
E911 address: Before you can use Wi-Fi Calling, you need to set up an e911 address on your account in case your location doesn't show up automatically to a 911 dispatcher. Learn how to set up your E911 address.
Active account: The service connects through T-Mobile service and uses your phone number, so your account must be active.
Phone that supports T-Mobile Wi-Fi Calling:
Some manufacturers state their devices have T-Mobile Wi-Fi Calling. Most of these devices work without any problems, but T-Mobile cannot guarantee their service unless you bought the device from us.
Wi-Fi Calling is included on most T-Mobile devices. Check the Devices page to look up your phone.
Wi-Fi Internet access: You must be able to use the internet on a Wi-Fi network.
For detailed requirements, see: Wi-Fi Calling on a corporate network.
Satellite Internet and cell phone hotspot are not supported.
Requires a minimum of 2 Mbps for upload and download speeds.
To set up T-Mobile Wi-Fi Calling on your device, open the Devices page, select your device, and use the help there.
When you first enable Wi-Fi Calling on T-Mobile, you must provide us with the primary street address at which the Wi-Fi Calling service will be used (“Your E911 Registered Address”). If you call 911 over Wi-Fi we may transmit Your E911 Registered Address to the 911 Communications Center, who may use it to help emergency responders locate you, but you may need to provide your contact information and current location. You agree to update Your E911 Registered Address if you plan on using Wi-Fi Calling service at a location different from Your E911 Registered Address. You can update Your E911 Registered Address by accessing your MyT-Mobile.com account or by contacting T-Mobile Customer Care. Not available in countries where Wi-Fi Calling is prohibited by law, including North Korea, Iran, and Syria.
