How To Fix AT&T Samsung Galaxy S8 Wi-Fi Calling Not Working On T-Mobile

The #Samsung #Galaxy #S8 is a previous generation flagship phone that offers several outstanding features to consumers. This is a popular model which can still outperform even the latest smartphone models today. This device sports a 5.8 inch Super AMOLED display, a Snapdragon 835 processor combined with 4GB of RAM, and a 12MP rear camera just to name a few. Although this is a solid performing device there are instances when certain issues can occur which we will be addressing today. In this latest installment of our troubleshooting series we will tackle the AT&T Samsung Galaxy S8 Wi-Fi calling not working on T-Mobile issue.

How To Fix AT&T Samsung Galaxy S8 Wi-Fi Calling Not Working On T-Mobile

Problem: I’m using a galaxy S8 AT&T phone. I just switched to Tmobile. I hate at&t and refuse to go back. I’m having a few issues, but I’ll do anything to keep from going back to that crappy company. First I’m unable to use wifi calling or any kind of text messaging. T Mobile told me that At&t probably has it blocked in their software and there’s nothing I can do except switch to tmobile phone. Is this true? Secondly, I couldn’t use the phone at all when not connected to wifi. I reconfigured my settings apn settings. Still nothing. Then tmobile told me to have network operator on “automatic”, but it said “select default setup” and other choice was “search for at&t microcell”.  So I instead clicked on “manual” and selected tmobile and now I have service, almost. I can text now (no wifi), but I still cant make phone calls, but at least it tries to dial now where as before it wouldn’t even try. It would just say emergency calls only. But for some reason it keeps losing the network operator and I have to keep going back in and selecting t mobile. I was trying to delete that at&t microcell, but don’t know how. We live in a rural area so I only have 1 bar most of the time, maybe two, but at least now it says 4g where as before I had NO network. Any suggestions. I just paid this phone off and really don’t want to switch.

Solution: Since your phone is originally an AT&T device which is now being used on the T-Mobile network the first thing you will need to do is to verify that your phone has been network unlocked. When the phone has been unlocked it will be able to work on different carriers.

The best way to check if the phone has been unlocked is to use a SIM card from a different carrier. In your case I suggest that you try using a different T-Mobile SIM card to eliminate the possibility of the problem being caused by an issue with the SIM. Check if you are getting service with this other SIM card. If there is no service then you will have to get your phone unlocked first.

The next step is to make sure that the phone has the correct APN settings. It’s likely that this device will still be using the AT&T APN settings so you should change this to the T-Mobile APN settings.

To access your phone APN settings

  • Go to Settings, look under Wireless & Networks or tap the Connections tab.
  • Tap Mobile network. You may need to touch More settings, More…, or More networks first.
  • Tap Access Point Names.
  • Tap the T-Mobile APN if one is available. If not, press the Menu key and touch new APN.

The T-Mobile APN settings are as follows

  • Name: T-Mobile
  • APN: (for LTE devices) or (for non-LTE devices)
  • Proxy: <Not set>
  • Port: <Not set>
  • Username: <Not set>
  • Password: <Not set>
  • Server: <Not set>
  • MMSC:
  • MMS proxy: <Not set>
  • MMS port: <Not set>
  • MMS protocol: WAP 2.0
  • MCC: 310
  • MNC: 260
  • Authentication Type: <Not set>
  • APN Type: default,supl,mms OR Internet+MMS
  • APN Protocol: IPv4/IPv6
  • APN roaming protocol: IPv4/IPv6 or IPv4 only when roaming internationally
  • Turn APN on/off: Grayed out unless there are multiple APNs
  • Bearer: Unspecified

In order for Wi-Fi calling to work on your phone you should first setup an e911 address on your account. You can do this from the T-Mobile website. If properly set up you should be able make and receive calls and texts (SMS & MMS) over a Wi-Fi connection. You should also make sure that the Wi-Fi calling option of the phone is activated.

  • Register your E911 address at My T-Mobile.
  • Turn on Wi-Fi.
  • From the Home screen, swipe up on an empty spot to open the Apps tray.
  • Tap Settings > Connections.
  • If necessary, slide the Wi-Fi switch right to the ON position.
  • Tap More connection settings.
  • Tap Wi-Fi Calling.
  • Slide the Wi-Fi switch right to the ON position.
  • Select the Wi-Fi preferred or Never use Cellular Network to turn on Wi-Fi calling.

In case the problem still persists then you should consider doing a factory reset in recovery mode. This will revert the phone back to its original factory condition. Make sure to backup your phone data before performing this step.

  • Turn off the phone.
  • Press and hold the Volume Up key and the Bixby key, then press and hold the Power key.
  • When the green Android logo displays, release all keys (‘Installing system update’ will show for about 30 – 60 seconds before showing the Android system recovery menu options).
  • Press the Volume down key several times to highlight “wipe data / factory reset.
  • Press Power button to select.
  • Press the Volume down key until ‘Yes — delete all user data’ is highlighted.
  • Press Power button to select and start the master reset.
  • When the master reset is complete, “Reboot system now” is highlighted.
  • Press the Power key to restart the device.

Once the reset is complete check the APN settings of your device and make sure that it is correct. You should also make sure that the Wi-Fi calling setting is activated.

If the problem still persists then this is most likely caused by software compatibility issues. You should consider flashing a T-Mobile firmware on your S8 phone as this will most likely fix the problem. Refer to the Sammobile website for the instructions on how to flash your phone.

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