Wifi calling is essential in many areas which have no decent direct mobile carrier signal.  Wifi calling uses your home or office wifi and your Internet connection to transport your cellular conversation and/or text messages to/from your cellular carrier.  All of the main mobile carriers have provided wifi calling since about 2017 and most of of them have emphasized it over microcell technology since 2018.   AT&T have mainly discontinued support for microcell tech and support only wifi calling for areas with no direct cell carrier signal.  Tmobile/Sprint and Verizon continue to support microcell tech (Verizon call it a network extender).

For Tmobile/sprint and verizon customers, it is advised that you use a network extender rather than wifi as microcell tech has been quite reliable whereas wifi calling seems to be subject to a variety of issues.  For those who must use wifi calling read on.

Brief tips to help resolve / improve wifi calling issues.

The single most significant issue we see in our area is that many phones behave badly in the presence of a very low power cell tower signal.  A very low power cell tower signal will not be enough to make a call or even send a text, however many phones get confused by this low power signal, even when they are supposedly configured to use wifi calling.   The tips below are aimed at persuading your phone to avoid low power cell tower signals and instead use wifi for calling.   Note that the best way to fix this problem is as noted above, buy a microcell and install it in your house.

1- check your phone has wifi preferred for calling and data. Usually the default setting on this is cellular preferred. If wifi is preferred then try switching the setting and see if it makes a difference.

2 – Independent of #1 try to put your phone in airplane mode when you are home but w/ wifi enabled. Some phones airplane mode automatically disables wifi as well as cellular so you have to manually turn wifi back on. Other phones only disable cellular when you enable airplane mode. Of course you will need to remember to disable airplane mode when you are back in range of a cell tower. If you are careful to enable airplane mode + wifi at home and disable airplane mode when away from home, monitor if the text send/receive situation improves. If you aren’t careful to enable/disable this then it won’t do much good to try and monitor if it improves since you won’t be sure what improved it.

3 – If all the above dont improve try power cycling your phone each time you come home from away from home.   Monitor send / receive texts to see if this improves the situation

Following are some Internet links to various to various cellular phone issues  and how to troubleshoot / resolve.  These are really examples of the kind of info that is available on the Internet by simply searching (googling) for terms like “wifi calling not working.”

 

ATT issues:

Someone having the same problem who posted to ATT forums but got no help (2018); https://forums.att.com/conversations/data-messaging-features-internet-tethering/texting-with-wifi-calling/5deff962bad5f2f606b2b5b0

Multiple people having similar problems in 2017 posted to ATT iphone forum, ATT support responded w/ some instructions to troubleshoot: https://forums.att.com/conversations/apple/inconsistent-wifi-calling/5df00ebbbad5f2f6061bf0ae. Part of the suggestion list was an ATT troubleshooting tool: https://troubleshoot.att.com/devicetroubleshoot/index.html#select-device/0 .

This one illustrates how messy wifi calling can be, particularly w/ phones that move in and out of coverage, and how to help address this by forcing the phone to use only wifi calling (airplane mode w/ wifi on when at home for instance): https://forums.att.com/conversations/network-coverage/no-service-at-home-and-wifi-calling-stops-working-too/5defcb18bad5f2f6067976b0

Verizon wifi calling:

Verizon support info

Common issues w/ Verizon wifi calling

Iphone Issues:

General Iphone Troubleshooting for wifi calling

Iphone 12 wifi calling issues, potentially fixed by IOS update.