imageclass MF249dw - can't print from multipurpose tray

 

I am trying to print from the multipurpose tray (assuming that's the name of the top tray) using custom-sized paper of 4.5 x 6.38". I've changed my printer settings and the laptop printing settings to be the same size. However, I'm getting the error "No paper: MP tray. Load paper". There is definitely paper loaded. How do I get it to recognize that there is paper?

 

Paper is loaded with the short edge in, and the printer makes a beep when I slide the paper in. So it seems like it's recognizing it. But the screen still says "Load paper".

 

I have reset, unplugged and hard reset, and downloaded all recent drivers. What else can I do??

 

Thanks in advance for your help!