Mobile data stops working each day since Android 9

[SGM26]

Since updating my Samsung S8 to Android 9 Pi every day my mobile data will not work.

It shows the 4G icon and mobile data is turned on however there is no connection. I must restart my phone in order to get a working connection. Happens every day since the update.

I've tried resetting the APN, cleared the cache partition, reseating the SIM card, etc, nothing works except restarting the phone.

After restarting it will be fine until some time the next morning (not sure which as I get up around 11am each day).

Is there a fix for this? I really don't want to have to restart my phone every day. 

[BandOfBrothers]

Hi @SGM26 

That's a conundrum. 

I have the Samsung One Ui  / Pie update on my Samsung Note 9 with no issues. 

I have a Duos Hybrid version so use two different network sim cards and mobile data works fine. 

As a process of elimination can you put your phone in Safe Mode which disables your downloaded apps and leaves the stock ones working and then use mobile data to see if the issues stops.

If it stops then this is probably a downloaded app that's causing this so start deleting your most recent apps one at a time.

If it continues then as a further process of elimination can you try your sim card in another phone.

Also a Vodafone Highstreet Store can replace the sim card via a sim swap if the sim card is degrading.

Check the phones own internal data monitor to see if any restrictions have been set.

A Samsung Experience Store or Samsung Service Centre can run a diagnostic test on the phone.

In regards to firmware rollback Samsungs stance is that you cant. 

However if you use Google Search you'll find methods.

A person doing this does so at their own sole responsibility knowing that a phone can be put Into an unusable state and possible manufacturing warranty being voided.

[SGM26]

I'll give that a try tomorrow when it happens again. 

It's just odd that after the restart it works fine until the next day. 

[hrym]

The usual cure for post update issues is a factory reset.   I know this is a pain, but would be part of any repair process, so you won't lose anything by trying it yourself, once you've exhausted everything else (I assume you've tried toggling mobile data in settings?).   Don't forget to back up your content and remove any sd card as the process sometimes formats them.