Specific SIM(number) not registering to network

[Chris_G]

I have been tearing my hair out trying to solve this all day:

Yesterday I realised I was receiving no data and upon checking it seemed I was unable to register with network. This morning, same problem. I have tried all troubleshooting, restarted phone, flight mode, cleaned SIM, reset network, reset all settings etc etc so eventually went out and got a replacement SIM, same issues.

I have tried both o2 SIMs in other devices, they work fine, which would lead me to think the issue is with my phone. Now sense is really puzzling is, I have also tried 2 Vodafone, 1 EE and 1 Tesco SIMs in my effected phone that also work perfectly! The problem is specific to the combination of my phone and the o2 SIM. (I don't have another o2 number to try) It had all been OK for the last couple of months with this device.

Have tried a full factory reset, still seeing the same issues. Any ideas!?

[Cleoriff]

@Chris_G 

If the sims work in other phones, then it's obviously a phone issue. You don't say what phone you have so ypu may be better off phoning the manufacturer to see if they can help with some sort of diagnostic test?

If you do want to contact O2, all ways are in this guide Guide: How to find help & contact O2 

[Chris_G]

Well this is what I thought, but why would 4 other SIMs from other networks work just fine?

It's a Samsung S24 Ultra that I have only had a couple of months. Do Samsung offer this sort of service? I went through an online help guide that said to arrange a repair? Is this the best way to go?

[Chris_G]

Well I assumed the same thing but why would 3 other networks work with no issue?

It's a Samsung S24 Ultra that I have only had 2 months, this is the first issue I have had. Do Samsung offer such a diagnostic service? I tried their step by step guide and that ended with suggesting sending for repair. Is that the best way to go?

I have a warranty with Cex where I picked it up (as good as new) but I fear I will have a hard time proving a fault with them.

[Enlli · Accepted solution]

Ah. CEX

Wonder if this is an ex O2 phone that someone sold to CEX then recently reported it stolen. O2 may have blacklisted it but it may take time for that to expand to other networks 

[MI5]

@Chris_G 

Take it back to cex with the sims to show it's blocked by O2.

https://www.checkmend.com/uk/

[Chris_G]

O2 support confirmed the IMEI was barred and have unblocked it. A definite lesson in buying second hand devices!

Thanks for your help all

[Enlli]

 Glad it's sorted

[Cleoriff]

@Chris_G 

Pleased it's now sorted. Bit annoying that CEX didn't run their own test on the IMEI!