4G mobile data not working with Samsung A320 and O2 SIM

[irhm]

My Samsung A320 (2017) seems to be in a state, since Feb 2023, where the mobile data doesn't work properly - no icon in top bar with 4G; occasionally it will come up after a while if the signal is strong.

I have had a replacement SIM from O2, but that did not make any difference.  Strangely, my SIM does work if I put it in another phone, and SIMs from other phones (not O2 as I don't have access to one) work in the A320.  I have reset the APNs to default and still no joy.

I thought the phone had a hardware fault, but then why would it work with SIMs from other phones?

If the Network mode is set to 3G, it shows H+ icon, and if set to 2G, shows E icon.  But when set to LTE/3G/2G auto connect, there is no mobile data icon.

I have a pay monthly contract, and APN is set to O2 Pay Monthly (mobile.o2.co.uk)

There is an outstanding fault on a mast near my home (OX5) but I get the same symptoms in other areas.

So it seems that something is incompatible between the phone and O2 4G.

Any ideas on how to fix?  Maybe some weird config setting?

[Cleoriff · Accepted solution]

@irhm 

Check out these guides Guide: How can I sort out my network issues? 

Guide: Is the network down for me or everyone?  and

Guide: Do you have poor coverage / signal Indoors? This may help Explain / resolve it 

I also suggest you download the My Network app> You can keep track of mast repairs and report issues

https://www.o2.co.uk/apps/my-network 

Give O2 a call on 202  or 0344 809 0202 (Contract) 4445 or 0344 809 222 (PAYG)

Or you can message O2 on Facebook ( https://o2uk.co/O2CFB) , Twitter ( https://o2uk.co/O2CTW) or Instagram ( https://o2uk.co/O2CIG), hopefully they should be able to help.

[irhm]

Thanks @Cleoriff for the ideas, but I fear questions to O2 will not be very fruitful - or no more than my post here. What I really want to know is whether my phone is faulty and I should get a replacement.

[MI5]

@irhm 

You'd be wise to speak to Samsung directly https://www.samsung.com/uk/support/contact/

[irhm]

Update:

With more patience I've found if I wait long enough (like several hours) the 4G icon does appear eventually and it all works.  But that is not very convenient - eg if moving from wifi coverage to mobile data.

I got another fairly new identical phone (SM-A320FL) from eBay but it has exactly the same behaviour.

So I'm now thinking it is some incompatibility between O2 and my phone.  The only explanation I can think of is that O2 changed their network protocol around Feb time (maybe for 5G) and my phone doesn't cope with it.

I'm reluctant to move from O2 as I got a good deal when they took over TalkTalk customers.

I have posted a message on Facebook (suggestion from @Cleoriff ) so will see what the response is.