Phone not allowed

[NB99]

Husband purchased new boxed iPhone 12 for my birthday. Initially set up with Vodafone sim, no problem. Activated new Telstra prepaid and had number ported from Vodafone to Telstra. New Telstra sim shows SOS only, despite numerous resets and restores from iTunes the problem is persistent. There are no active locks from Optus (the network from which phone was originally purchased). 

[Dowser]

Does the prepaid Telstra SIM work in a different phone?

Even though you said that you have done “numerous resets”, please try the following one.

Reset your Network Settings.

Go to Settings > General > Reset > Reset Network Settings. This also resets Wi-Fi networks and passwords, cellular settings, and VPN and APN settings that you've used before.

Source: 

https://support.apple.com/en-us/HT201415

Then restart the phone.

[NB99]

Thanks Dowser. Yes sim works in my Samsung S7. I have done the network reset at least a couple of times...

[Dowser]

---

@NB99 wrote:

Thanks Dowser. Yes sim works in my Samsung S7. I have done the network reset at least a couple of times...

---

Are you saying that when it’s in the Samsung the Telstra network is connected to and is functional for calls and data?.

[Dowser]

Also, when the Telstra SIM is in the iPhone 12 what does it say under Settings > Mobile?.

You could also check for a Carrier Settings update.  Leave the SIM card, connect to WiFi,then go to Settings > General > About. If an update is available, you'll see an option to update your carrier settings.