Sound comes out of my headphones or speakers incorrectly. Why is this happening?

There are 3 things to consider: settings, operation, and connection.
Please check each in the following sequence:

1) Confirm the settings on the Serato DJ Pro screen
1. Check if the [Error: Failed to connect audio!!] or [Driver Not Installed] message shows at the bottom of the screen.
If either shows, see the DJM-S5 FAQ > [[Troubleshooting - Serato DJ Pro] > "The message [Error: Failed to connect audio!!] is shown, or the virtual deck disappears immediately on the Serato DJ Pro screen."]](DJM-S5 FAQ link).
2. Click the [My Serato] icon in the upper right area of the screen.
3. Check that [Serato DJ Pro is hardware activated.] and [DJM-S5] show on the screen.
If they don't show, see the DJM-S5 FAQ >[Troubleshooting_Serato DJ Pro] > "The Serato DJ Pro screen doesn't react to anything I do on the DJM-S5 when it's connected.".

2) Check the volume level operation
1. Play a track.
2. Set the TRIM knob to the center (12 o’clock).
3. Slide the channel fader to the top.
4. Slide the crossfader to the center.
5. Turn the MASTER LEVEL knob to 2 o'clock.
If the master level indicator lights up more than half way, there’s no problem in the settings and operation.
If you don’t hear any sound from the headphones at this point, check the following:
6. Turn the HEADPHONES MIXING knob to the center.
7. Turn the HEADPHONES LEVEL knob all the way to the left.
8. Slide the headphones cue fader to the center.
9. Turn the HEADPHONES LEVEL knob slowly to the right.

3) Check the connection of speakers and headphones
For details, see [Example of connections] in the Quick Start Guide.
Even if you’ve already connected them, disconnect and reconnect your speakers and headphones to make sure they’re connected properly.
*It's not possible to output audio from PC/Mac speakers.

You can read the Quick Start Guide [here].