Sterio mode not working

[Mahesh Krishna]

I downloaded one youtube video which I can only hear in one of earpiece.
I tried to change the mode of output device to mono mode using below command
>>> pacmd load-module module-remap-sink sink_name=mono master=alsa_output.pci-0000_01_00.1.hdmi-stereo-extra1 channels=2 channel_map=mono,mono
After rebooting I'm unable to unload this module
I tried to reinstall pulseaudio but still I could not change output to sterio.
Some one help me to completely reinstall audio drivers in debian9

[arochester]

Are you sure that i is stereo?

Could it have been recorded in mono?

Would you care to share the URL with us?

[Mahesh Krishna]

I used graphical sound testing tool
there is no sound generate during the test.
But I get sound output when I play videos but mono
I used to hear front left and front right when perform the test before