Honor X9b 5G Not Sending SMS – Insert SIM Error

I have been experiencing an issue with my Honor X9b 5G phone for the past four days, and I have not been able to resolve it. Whenever I try to send an SMS, the device repeatedly displays a “Insert SIM card” warning. Even though the SIM card is properly inserted, the phone behaves as if it cannot detect the SIM and does not allow me to send messages.

When I test the same Turkcell SIM card in other phones, I can send and receive SMS without any problems. This means there is no issue with my line or SIM card; the problem is entirely related to my Honor X9b 5G device. Phone calls, internet access, and all other features work normally — only SMS sending triggers this error.

I have not yet contacted technical service or my carrier about this issue, but since I am confident it is software-related, I request that Honor provide a clear software solution, update, or guidance to fix this problem. I want the issue resolved so I can use the SMS function on my device without any problems.