Hi, had an htc m9 for a while, worked on familywhere. I now have a Oneplus 5t (chinese phone) that TMobile definitely doesn't sell. Is this the reason why I can't be located on familywhere? Because I also noticed that I cant set up my phone on my tMobile because it cannot be found under the phone list.
Welcome to our Support Community! We cannot guarantee compatibility, however, sometimes disabling WiFi will do the trick. As far as changing your device on My T-Mobile, since we do not carry that device, we may not have it as an option to set your phone as.
Please let me know if you have any other questions!