Confirm that the audio balance is not set to the left but in the middle!
Swap speaker connections to make sure the problem doesn't follow the speaker indicating the wiring to the speaker or speaker is bad.
Need to confirm that the input to the selected device is OK. Swap input RCA Red and White connections from the source. If an optical confirm that the source balance if the setting is available is set to middle
On many upgrade receivers as this Sherwood there is a test feature that confirms with an audio beep the speaker balance and connections. Look for a "Test" button.
Beside swapping the speaker connections left to right swap the speakers between the A and B speakers. See image for connection detail.