This is a great place to get support, find answers and tips,
Thank you for posting your query, I'll be more than glad to help you out 🙂
As I understand you are getting the message - "monitor going to sleep",
Don't worry as I'll be glad to help, however, to provide an accurate resolution, I need a few more details:
Did you know holding the power button for 20 seconds or more either releases or locks the OSD menu?
Have you attempted to hold the button after receiving the message-"On Screen Menus are locked"?
Does the message appear on an alternate monitor?
While you respond to that, I recommend you check with another monitor and if the issue doesn't occur on the other monitor, follow the below steps:
These messages are normal when the computer truly goes into sleep mode or loses the video signal (such as when the computer is turned off). However, if the monitor displays any of these messages when the computer should be displaying video, something is wrong.
If you suspect the monitor should be displaying an image from the PC instead of the message, use one of the following sections that match how the monitor behaves after the computer is powered on:
Windows opens, but after a while the monitor displays the message
Startup screens display, but the message opens before the Windows desktop opens
The message is the only item that displays on the screen