Chosen Solution
I tried following the instructions here https://support.t-mobile.com/docs/DOC-33…, because I am currently using t-mobile, but it didn’t seem to help me. How do I make the message go away? (I don’t care about Wifi calling btw).
I put my SIM card in the SD slot but upsidedown. We traded in phones. Thanks for trying to help!
Hi, Have you tried turning OFF WiFi Calling in your phone or make the cellular network the default option? Go to Settings > Wireless and Networks > more > WiFi calling
Hello, this problem causes when sim card slot doesn’t registered in Network, my advice is call your network administration for sim card registration. You should register sim slot by that IMEI code in your network operator.
i am not using a sim card so it should be i/o error instead
