A major problem with dB

Hello

I hope I could explain my problem right…

I opened a existing project in my cubase, and suddenly every time I want to duplicate a channel, the sound of this channel gone - becoming really really low, and the original channel also not make a sound as before. It’s look like the sound is about really low dB. If I’m using eq and make it really high by the parameters, you can hear a little bit.

After that a randoms channel started to have the same problem - a very very low sound

I’m working with Cubase 11 on Mac book m1 and it has worked perfectly until now.

I believe I press something by accident

I will be glad to any help

Thank you