NAD C326BEE speaker channel problem

Hi,

I have a NAD C326BEE stereo amplifier. The right speaker channel is buzzing, but the music is still heard. There is no problem with the left speaker channel. I have opened the amplifier and there is no visible fault in any of the components. Does anyone have experience with a similar error and how to fix it? I don't have much experience in repairing amplifiers yet, so any help is appreciated.

Thank you!