Sim network change problem

[kamrul-hasan-himel]

I cant be able to my sim networks because its no changeable mode.How can I change it?  Anyone please help

Thanks in advance

Device : S 21 ultra AT&T

[indiantrueindian]

What's your device model

[kamrul-hasan-himel]

S21 ultra At&T

[kamrul-hasan-himel]

Is there any chance to unlock it?

[Chaudhary]

Try flashing unlocked csc for your model no from samfw

[Hitesh02]

Yes try to change XAA csc code

[cs_member10]

Dear Samsung member,

Greetings from Samsung customer support.

We acknowledge your query and apologize for the inconvenience caused to you and will surely assist you regarding the same and please follow the easy troubleshooting steps which might help to solve the issue.

Kindly restart your smartphone once and also re-insert your SIM card.
Check device network in an open area: Kindly check your device in a different location/network coverage area.

Check device network mode settings
Please follow the below steps.
Step1: Navigate to the app's screen and tap on Settings.
Step2: Tap on Connections.
Step3: Tap on Mobile networks.
Step4: Tap on network mode SIM1 or SIM2.
Step5: Select network mode.
Note: We recommend setting device network mode as LTE/3G/2G (auto connect) mode.

Kindly do check the same SIM card in another phone or another SIM card on the same phone to verify the issue.

In case the issue still occurs. Please register your concern in Samsung Members Application (Open Samsung Members Application > Support> Tap on error report > Type your query > Send).

Thank you for writing to Samsung.

Warm Regards,
Samsung Customer Support