WiFi Calling Issues: Straight to voice mail, can't make or receive calls troubleshooting

Compiling a list of t-Mobile by calling troubleshooting procedures if you have any problems with WiFi calling food straight to voicemail cannot make outgoing or incoming calls or WiFi calling is just generally unstable this slash these procedures below may come in handy I compiled this from T-Mobile site as well as from the Android Dev site

Option 0)
After many calls to T Mobile about the lollipop update breaking my WiFi Calling. You know, not enabling. Here is a work around.
1. Go to Settings >> Networks and tap Airplane Mode while WiFi is on.
2. Wait for Airplane Mode to go from being grayed out to bold.
3. Enable WiFi. Wait for the connections to be made.
4. Disable Airplane Mode. And wait a few seconds.
WiFi calling will enable.


then install: app called wake lock to keep the wifi connected, as the normal no sleep when wifi setting doesn't work in the settings.




Option 1)
So if you've tried everything else, here are the steps:

1) Enable airplane mode.
2) With airplane mode still on, enable Wifi, making sure that you are connected to a router and have Internet access.
3) Long press WiFi Calling in the notification panel.
4) Change Wifi Calling setting from Wifi preferred to Cellular Network preferred and then turn it on. It will turn all selections gray and pretty much just be stuck there like that.
5) Reboot device. Connect to Wifi and after ensuring that airplane mode is off, long press WiFi Calling in the Notification Panel and select Wifi preferred and turn on Wifi Calling.



Option 2)
Cause: heres a service system file on the note 4 kitkat itself that bugs out if u connect to a different wifi hotspot WHILE wifi calling is still enabled. The wifi calling doesnt clear the cache automatically like its supposed to so the voice IP you are trying to talk through doesnt match the cache from the previous hotspot, causing people not to hear you or any automated phone systems getting amything from your end.

Resolution:  To fix this either you find the wifi calling thru app manager and clear just the cache or restart your phone. However if you restart your phone be sure your wifi calling is disabled before you restart. Its a good thing they are fixing this cache issue in lollipop



Option 3)
Steps taken to correct the issue with no effect:
• Performed a Master Reset on the phone (extremely inconvenient)
• T-Mobile have sent OTA updates to the phones
• We have replaced our expensive ASUS R7000 Nighthawk router with the T-Mobile CellSpot router to ensure that everything we can do to optimize the WiFi calling connection is in place.
• Reset my e911 address
• Cleared the cache

Option 4)
WiFi calling is pickier about network connections than web browsing, because if a few data packets get delayed a quarter of a second that hardly matters for web surfing but matters a lot for voice calling.  When WiFi calling on my phone stops working, the first thing I try is rebooting the phone.  Usually that solves the problem by getting me a better WiFi connection.  Theoretically just switching Airplane Mode off and on should also do that, but for some reason a full reboot works better for me than just going in and out of Airplane Mode, I dunno why.
If rebooting your phone doesn't solve the problem, ask your local networking geek to check whether your router lets TCP port 444 and UDP port 4500 through.  It uses TCP port 444 to register your location for 911 purposes, and UDP port 4500 for the actual calls.  You may also need to enable "VPN Passthrough" on your router, because under the hood it uses an IPSEC VPN tunnel.  The VPN encrypts your voice calls so people cannot eavesdrop; unless your home network is open (which I do not recommend) traffic on your home network already is encrypted, but of course Sprint wants to make sure your conversations are private when you connect to public WiFi at Starbucks or McDonald's or your hotel.
Note that nobody at Sprint tech support seems to know the above; it was worked out by some expert users who know how to use network analysis tools on their home routers.


Option 5)
Turn off WiFi calling.
It is connected to the WiFi, and the WiFi radio is asleep when the screen is off.
By defult a Tmo phone has WiFi calling on..... And it doesn't work for..... Beans


option 6)
Make sure in the settings that connection priority is set to voice instead of data. You could be missing some calls while using your mobile data.


See Also:


http://forums.androidcentral.com/lg-g3/480740-why-my-calls-going-voicemail-when-my-phone-has-signal.html




https://forum.xda-developers.com/tmobile-lg-g3/development/wifi-calling-lollipop-t3089142




https://support.t-mobile.com/thread/131501?start=0&tstart=0