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? 

[Rahul Lahiri]

I use T-Mobile. Here are two suggestions to try that had some beneficial effects for me:

1. In the network settings, select LTE/... instead of 5G/LTE/...  T-Mobile suggested this change and it certainly helped.

2. I can see a difference in behavior depending on whether I set the wifi preferred or cellular preferred. The link was a LOT more unstable when set to cellular preferred.

I am in a real quandary now. Samsung will not replace the phone. I am deeply entrenched in Android, and an iPhone is out of question. Not sure whether to get another S21 or something else. I would have gotten an LG, but LG seems to be trying to jettison their mobile phone business. 

[Mottoson]

Thanks for the tips, Rahul. It's really not great from them, is it? Maybe if enough people complain they'll have to do something.

[Rahul Lahiri]

@Mottoson  I think I know the source of the problem. Samsung is automatically optimizing for the network periodically, and for some strange reason, it is switching my manually set wifi priority to cellular priority. I do not know why they would change a manually configured option like this -- seems like a strange product decision to me, but they probably have their justification. I noticed that tiny little notification the last couple of times, and that seemed to show up predictably with my losing wifi calling. So now I am keeping an eye open for it, and switching the configuration back to wifi priority when Samsung changes it to cellular priority. 

Seems like a weird product decision, but if my observation is correct, then I can live with this. It's not a defect in the handset per se -- but likely a design choice reflected in all their phones. Keep an eye open if this is happening with your phone as well when you lose the wifi connection.

[jab1972]

Hi Rahul-Lahir

I am getting a very similar problem to you with my S21 Ultra.

I am on Vodafone UK and also find the WIFI calling stops working after a day or two.

The only way I can get it back is to reboot the phone.

Interestingly, I have also noticed that when the WIFI calling stops working, the VOLTE (4G calling) also stops working (Phone will revert back to a 3g signal as soon as I make a call)

Again, after a reboot the VOLTE works straight away again for a couple of days and then will stop (along with the WIFI calling)

I have spoken to Vodafone’s customer support a number of times and they say my account is definitely set up correct for WIFI calling and VOLTE and have absolutely no clue.

I have tried network resets/factory resets and this still happens.

Previously I owned a Note 9 for approx. 3 years and never had an issue with WIFI Calling or VOLTE not working.

I have also spoken to Samsung Customer support and they can only suggest its an “rouge” app causing this issue but I have no different or new apps on my S21 Ultra than I did on my Note 9.

WIFI calling and VOLTE are very important to me and this is really becoming very frustrating and annoying on such an expensive phone.

Can I ask, when you mention that your settings are changing from “wifi priority to cellular priority” where are you seeing this?

Many thanks

[stephennovosel]

Chalk me up as another S21 Ultra user who is experiencing cut outs on Wi-Fi Calling.  I'm on ATT in the U.S.  Just got the phone today.  

I will simply return mine for an iPhone 12 Max Pro (which my son has and it suffers none of the problems I've dealt with this afternoon with the Samsung).   Before I do anything rash, I thought it worth it to at least give Samsung Tech Support a chance to shine.  If they assist, I'll update this post.  

[jab1972]

HI stephennovosel

Can I ask if you got any where with Samsung Tech Support?

I am still unable to solve my issue.

A few days ago, I factory reset my phone and only installed Whatsapp, and the phone still suffered from the Wifi Calling and VoLTE service stopping working.

So, my issue is definitely nothing to do with 3^rd Party Apps.

I have now managed to get to the “Prefer call over Wifi” / ”Prefer call over Mobile Network” options with an app called “Samsung Band Selection” (It would seen my provider, Voda UK, software hides these options in the normal menus)

I have tried on “Prefer call over Wifi” and the Wifi calling will stay connected for hours ok until I leave the Wifi Area, travel and then reconnect to a Wifi Network again (same or different Wifi network, makes no difference)

At this point the VoLTE has also stopped working. (phone will revert to 3G when making a call with strong 4G)

A reboot of the phone, (regardless of if it is connected to a Wifi Network or not) will instantly restore both VoLTE and Wifi Calling (obviously Wifi calling when I next connect to any Wifi if not connected).

In my case the failure of both services is definitely linked and triggered by either the phone connecting to different Cell sites while traveling or the phone disconnecting/connecting to different Wifi Networks and something causes both services to fail until the phone is rebooted.

I am at a loss now what to do other than demand I return my phone to my service provider and cancel my contract (which is unlikely as I have had it 6 weeks now) or to just live with the issue and hope Samsung/Vodafone UK release an update that fix’s it.

Very disappointed.

[Rahul Lahiri]

Sadly I could not live with losing the wifi calling -- I was missing too many incoming calls. After countless tweaking of controls and factory resets, Samsung was kind enough to finally agree to take the phone back. I really appreciate the gesture on their part. I had to rush out and get another phone. Got an LG, even though I am not sure whether LG is still committed  to their mobile phone business. It's been 3-4 weeks since the switch -- not lost the connection even once. I am a bit disappointed that I had let go of the S21, but I didn't really have much of a choice. Happy with how the end result has turned out with the LG.

[Rahul Lahiri]

Hi jab1972,

I am not sure if the menus are identical across carriers / continents. I am reading this off my LG, but I think it was the same in the Samsung. I could see this in Settings > Network & internet > wifi calling > Wifi preferred. I would set it to wifi preferred, and the phone would periodically shift it back to cellular preferred.

[jab1972]

Hi Rahul Lahiri,

Yes, I have found you are correct, the menus are not identical across carriers.

It seems the Voda UK "hide" this option (and VoLTE) and it is always set as "Network Preferred"

I have managed to access these "hidden" menu options with an app called "Samsung Band Selection" but I am still having issues with the Wifi calling and VoLTE intermittently just stopping working.

It seems to be linked to if the phone travels and connects/disconnects to various Wifi Networks, the Wifi Calling and VoLTE will eventually just stop working, requiring a reboot to restore.

I am convinced this is a software issue with Samsung/Voda UK but I am getting no where fast trying to get is resolved!!!!

[Demondam555]

With a lot of us working from home, this is an essential service of the phone which Samsung is failing miserably at, currently. After the most frustrating time spent recalling clients and calls dropping regularly, I've found the stupidest way to stop this from happening. Turn on Airplane mode !!!! The Wifi turns off but just click it back on again. I've lost the ability to send receive SMS's but it's a trade-off that's necessary until they fix it. Can't be that difficult for them. COME ON SAMSUNG !!!. In case you forget to turn off Airplane mode when you leave the house you need to set up Bixby routines for in the house and out of the house.