Pixhawk can't connect to computer via USB or RFD

Hi. I have using Pixhawk 2.1 for almost 6 months and It was working properly. I have tried to connect storm32 gimbal controller card with telemetry 2 port today. It was worked properly first and then I have calıbrate the parameter “MNT_MODE;_IN” and I have selected the AUTO and then I have tried to reboot Pixhawk 2.1 and then It didn’t connect to computer when I tried. What I must to do? I think If I can reset to Pixhawk, It can be fixed but I couldn’t find how I reset the device.