Why my phone turns off when i put 2 SIM Cards?

[AC Question]

Hey guys, I bought Samsung Galaxy S7 and for 4 months i used it with one SIM Card. When i inserted the second SIM Card the phone turns off on every 10 or 15 minutes. Can someone explain me why is this happening? How should i fix it? Thank you!

 

[B. Diddy]

Welcome to Android Central! Do you mean it randomly reboots? Can you ask for a replacement SIM, just in case it's a problem with that 2nd SIM card you inserted?