S21 -- wifi calling issue. Repeately dropping out of wifi calling mode.

[Rahul Lahiri]

I use T-Mobile. With the new S21, I am periodically losing the wifi calling ability. The setup is wifi calling preferred -- the cellular signal is pretty weak around my home. Wifi calling works great immediately after a reboot. Within a day or less, the wifi calling ability quietly drops -- no error messages. Wifi itself is still perfectly fine, and internet connectivity is not affected. The only way out of this state is either to stop and restart wifi connectivity, or to reboot the phone. The last 4 years I had a S7 and had no issues with it. I transferred the same sim to the S21.

Unfortunately Samsung help has not been all that helpful. They have had me clear cache from a protected mode restart, cleared the cache for the phone app, reset my network configuration, reset all configurations, ... -- but the problem keeps happening. 

I checked with T-Mobile, and all configurations at their end seem to be fine. The only thing that they suggested to achieve parity with the S7 is to select the network config without 5G, and see if I still have the problem. I switched to that config a couple of hours earlier. Waiting to see how this holds up.

Anybody else facing this problem on the S21? 

[The Baron]

Hi There, I have also had this problem recently but the solution that worked for me is as strange as the problem itself. I came here looking for the same answers it seems everyone else is after, and in doing so I've seen many people who have commented that they had "WiFi preferred" as the manual setting and that it dropped out when making or receiving a call - I had exactly the same problem and also had my preference set to "WiFi preferred". 
Juts to see what would happen I switched the manual setting to "Mobile Network Preferred" and for some unknown reason the WiFi Calling now works without issue! I can't explain why or what has happened but it has worked for me. 
I also had no issue with my earlier model Samsung (S9) and to be honest have not had any trouble with the S21 until very recently - I don't recall any software update that correlates to the issue either, so it's a mystery. In any case the switch to "Mobile Network Preferred" fixed it for me, so hopefully it might help others. 

[FyShy]

I am bumping this thread. Its' been active for 4 years and Samsung does not appear to have either acknowledged the fault or done anything to fix it. To recap everything that has been tried (from others in this thread) as best I can:

* I have an S21 FE 5G. This issue seems to be related to the S20 and S21 models but does also seem to affect other later models such as the ultra series as well. Older models such as the F8/F9 seem unaffected, although not all providers have implemented wifi calling support for older models, so a downgrade isn't likely going to be an option. I have a perfectly good S8 Active here that I upgraded from because I needed Wifi Calling. That was a $1000+ waste of money given it doesn't work properly. The symptoms I and other people have observed:

* Others have reported switching to a non-Samsung handset, such as LG, and this has resolved the problem. I have not done so because I generally love Samsung and really want to find a less scorched-earth way to solve this.

* Many people have tried a clean factory reset and this has not resolved the issue. So it would appear to not be interference of any 'rogue' software as Samsang has suggested.

* I and other people live in areas with very low or no cellular signal but do have a good internet connection with a Wifi Calling compatible wifi router. For reference - I get 70Mbs up and 30Mbs down, so its not a problem with the quality of my internet connection either.

* Wifi Calling for me and others does work periodically. This is not a problem with initial configuration of Wifi Calling - please stop suggesting that and making YouTube videos of how to turn it on. We know already.

* Wifi Calling is correctly turned on and does work. It just doesn't stay working.

* The period of time it stays working before turning off seems to vary from an hour to several days. There is no apparent frequency or time of day when the drop out occurs. I've been monitoring it - there is no useful pattern to it.

* WifiCalling turns off periodically without any apparent cause (such as moving into weak WiFi signal areas, or  accidentally turning it off manually - seriously who does that). The wifi/handset icon just goes away and it silently stops working, and therefore no longer receives incoming calls or text messaging. Note - Wifi internet is still working fine and other internet-based communications, such as WhatsApp still work fine at this point. It's not an internet connection issue.

* The impact of this issue for me and others is huge. For me this is critical because I am an emergency service first responder and reply on this working with I am on call from home.

* Changing from Wifi Preferred to Cellular Preferred does not solve the problem for most people.

* If there is any level of mobile network signal, even no bars, a Wifi call will initiate if it's currently working, but I can't start a WifiCall unless there is network signal, regardless of Wifi Preferred setting.

* The same issue has occured at different times with my Wifes S20. So it's not a network issue or a wifi issue.

* My carrier has looked into it from there side and cannot see any indication of a problem on the network.

* Going into flight mode and back out will usually solve the issue, as will rebooting, or removing and replacing the sim card. It does not resolve on it's own and needs to be manually restarted.

* Despite another poster suggesting there is some warning of a configuration change popping up for them the predicts it, this is not happening for me, nor is the system-forced setting change they describe.

* This problem is wide-spread. I have found many many people on different forums describing exactly this issue from different countries across different models and different carriers. This is 100% a fault with the phone or software.

* Everone who has reported trying to talk to Samsung Support about it seems to have gone nowhere, with the best resolution being Samsung agreeing to refundiung the purchase of the handset in good faith without acknowledging the fault.

If anyone reading this thread has found any kind of software update or fix for this, please post this. It seems unlikely there is any interest from Samsung in dealing with this in any way.