I bought my new S9+ yesterday (europe simcard only) in Germany. I inserted my winsim (O2) in it and made my first call and it lasted for 30+ minutes. Then I insterted my Indian SIM card (Airtel) and the mobile displayed network locked SIM card inserted.
I took the simcard out and left it overnight. This morning, I tried using the Indian SIM card again and it displayed the same message. I tried switching my other Germany SIM card (lycamobile) and it works.
Kindly help me. Looking forward to see your replies.