Invalid silent mode turn off itself after receiving/making a call

[Berde]

everything was ok for few months i've been using miui but now when i'm in silent mode and i receive or make a call my phone automatically turn silent mode off, i dont know why. eg. when i have silent mode and and someone call me two or more times, the second call is loud. please help me

my phone is se mini pro sk17i

 

[Pele]

have you checked the settings within the phone app and also settings volume/vibrate settings