Why can't AT&T even do something as simple as this without screwing it up. I'm not sure why this feature is screwed up, but this is pathetic. (I also tried the stock text app and it was the same way.
I had to physically uninstall Textra (the text app I use) and re-install it again before I could send texts even in the normal way. However, this time, after turning wifi calling off, I wasn't able to send pictures via text at all. I have tried it on three seperate wifi access points with the same results. This morning, I tried it again and once again, although the wifi calling emblam was on, the phone refused to make a call or send texts via wifi. I was able to make a call and send a text via wifi.so I though it was OK now. I tried it again and put the phone into airplane mode, re-enabled wifi, and made sure wifi calling was enabled. I then did several re-boots and cleared the Cache in recovery before restarting the phone. Especially when you are switching from one mobile to another phone. You need to know that the Smart Switch is preloaded on Galaxy S7. With Smart Switch for Galaxy S7, transferring data or files has become so much easier. After that, please follow the instructions on the screen to continue. You can then choose to transfer via USB cable or wireless.
The wifi calling emblam was in the notification area and wifi calling was turned on but it still wouldn't work for calls or texts. (You can search for Smart Switch in Google Play Store.) Place the Samsung devices near to each other (within 50 cm) and then open Smart Switch on them. However, when I put the phone into Airplane mode and re-enabled wifi, it would not make a call, it would just pop up a message stating the phone is in airplane mode and it must be turned off to make calls. I turned on wifi calling and set everything up.again it went fine.
SAMSUNG SMART SWITCH FOR MAC NOT WORKING WITH S7 UPDATE
I took the latest S7 update that included wifi calling and everything seemed to work fine.