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Mobile data not working after disconnection from WiFi


This fault occurred after the most recent update of my S9. When my phone disconnects from a WiFi network (whether manually or once out of range) my phone will display either a 4g or H+ but no data is sent or received and apps/browser will confirm the phone is offline. The only way I can get mobile data to work again is to either toggle it off and on or go into flight mode for a short time.

This happens on any WiFi network (home, work, public) and I have the auto WiFi switcher features tuned off. Has anyone else come across this issue? I reset my network settings but that hasn't helped. Would prefer not to have to factory reset to correct a fault which Samsung seem to have introduced themselves. 


I managed to get it sorted
I called network provider and asked them to resend the network settings by txt Msg.. They sent it and i installed and works well again.

This worked for me also. I contacted Three and they resent my network settings. Now my 4G is up and running perfectly again.

Same here. Rather annoying on 3.


Hopefully that'll issue a fix soon.



First Poster

yes same issue on THREE UK network. Seems some people who reset default APN settings got it fixed but didnt work for me. 

3G works fine

Only issue is 4G

I disabled VoLTE and this worked for me, but obviously I want to be able to use VoLTE!

Have spoken to Three and Samsung and both blame eachother


We all need to make them both aware of the issue so they provide a fix in next software update

when will there be a fix for this? many people affected. its not a sim or phone fault.

It's the most irritating thing. Switching on/off data only works some of the time too .

Same for me. Will ring three tomorrow and see what will help. 

Problem is likely to be with the Samsung update. I guess three will send the APN details again, but will fail once you switch between WiFi and data.


I can't believe something such as this was never tested.


The extra clicks to change the settings seems so primitive. 

I've disabled VOLTE for now. Works well. Once Samsung fix it I'll re-enabled.


I've also started to experience this problem (I have the dual SIM variant but only use it with one SIM and an SD card). Like others, I've found that either disabling VoLTE Calls - or toggling Flight Mode on and off when switching between WiFi and 3G/4G - restores my cellular data connectivity.


However this is not a solution, the phone did not do this out of the box. I'm pretty hacked off that I have to disable VoLTE Calls which is a useful feature for me.


Enabling/disabling Wifi Calling makes no difference. However if I have VoLTE Calls enabled while connected to a wifi network, if I disconnect, immediately I have no cellular data. It magically starts working the moment I disable VoLTE Calls in the Settings -> Connections -> Mobile Networks menu.


My phone was given a full ADB diagnostic by the Samsung engineers at a local service centre last week and nothing untoward was indicated by the tests. This appears to be a new bug introduced by the most recent OTA update.

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