I am using Samsung galaxy s21 fe.

I am using 2 sim card from last 8months, In SIM 1-Jio & SIM 2- Airtel and it is perfectly working but from last 5-6 days my SIM 2 showing Unknown Number so changed the SIM card slot from SIM 2 to SIM 1 but now same issue showing in SIM 1 slot and SIM 2-Jio working fine.

So I inserted my Airtel SIM in another device & it is working in that device so I reinserted in my device and it is showing same Unknown Number issue.

So please help me to resolve this issue.