Hello AmrfA1970,
I search our online knowledge base and found this article for Tray 3 open message. f you are still having issues after trying these steps, I suggest that you call into our support department for assistance @ 1-800-821-2797.
My printer cannot continue printing due to Tray 3 error saying it is open but even how many times open/closing the tray it still cannot print (printer is set to print in Tray 1).
Please help how to disable Tray 3.