Please refer to the following steps:

1) Unplug and reconnect the S-switch. Then, make sure it is connected to the monitor properly.

2) Reset the monitor by using "Reset All" in the "System" section of the main menu in the OSD.

3) Try to recreate the conditions that cause the random colors when using an S-switch. If you are not sure what those conditions are, you can press the  1/2/3 buttons repeatedly to test functionality. 4) If the problem persists, please contact our online service team for more assistance.