Sim wont work in another 02 phone

[Aaron5]

My phones been acting up, so I tried to put my 02 sim into another 02 phone but it won't. Does anyone know the solution to this? Is it just a case of getting a new sim?

[MI5]

@Aaron5 

Sounds like it may be the sim that is the problem rather than your phone?

You need to contact O2 for a new sim card.
All numbers are in this guide Guide: Coronavirus Community Help and Support 
When you call, you will be asked for the reason you are calling.
Stay silent for 15 seconds and you will be taken to the keypad options.
Press 2 for Everything Else
Press 5 for More Options
Press 7 for Anything Else which will put you though to someone.
You can also try saying "Upgrade" or "Fraud" to be connected to an advisor.
8.00am is the best time to call if you can.

[Aaron5]

Sorry I should have explained in more detail my phones battery is knackered thus I need to use another phone, but my sim wont work in any other 02 phone.
Thanks for the reply

[MI5]

@Aaron5 

Your O2 sim should work in any O2 phone, but makes sense to try another sim to rule it out.

Are you sure the other phone still works OK?

Are you getting any error messages at all?

[Aaron5]

The other phone works fine its only a year or 2 old but been kept very well.

When I put my sim in the other phone a notification comes up saying "phone not allowed for voice"

So would the phone need unlocking but doesn't make sence

[MI5]

@Aaron5 

The phone could be blacklisted for some reason.

Check online to see if it comes up as such on sites such as imeicheck.com etc

[Aaron5]

I will. try its another Samsung but not an s9 it was my mums phone before her new one so I don't see why it would be blacklisted but I will try thank you