Did you figure out what the issue was , I have the same problem .After unlocking my TMobile issued Samsung phone and switching to Mint Mobile wifi calling option is disabled. Cant get it back even after multiple attempts .Please let me know if there is a way to enable it
for the ppl who are having the same issue, would you guys go to your setting -> about phone->software information -> check carrier configuration version.
I got 3.370001 which seems the latest version has hightest restrictions, guess that's culprit stop us using Wifi-calling, my wife has unlocked T-mobile note 9 that run higher Android version but lower carrier configuration version, i popped my mint sim card i am able to see wifi-call and works like a charm.
pls reply and let me know which version you have?!
I am also experiencing this issue. Note 8 with Oreo 8.0.0 on Sprint. Calling Plus shows Wi-Fi Calling enabled, went through the 9-1-1 setup procedure fine but with no service and only WiFi, I can't place calls or send texts. I also can report that Sprint's LTE Calling does in fact work on 8.0.0. I get the notification on my status bar. I do not get any notification in my status bar for WiFi calling. I'd be happy to provide any extra detail if needed.