printer won't copy; indicates mismatch between paper selected and size; I haven'te changed the size.

[TomHR64]

printer won't copy; show mismatch between paper size and document. They're both letter. I have not changed settings

[Deep_World]

Hi @TomHR64,
 
Welcome to the HP Support Community!

Thanks for reaching out!

I understand how  it must feel when your printer shows a paper mismatch error even though you haven’t changed anything. 

Could you please share your printer’s model number?  

In the meantime, here are a few steps you can try:

1. Check paper tray settings: Make sure the tray is loaded with Letter-size paper (8.5 x 11 inches) and that the paper guides are snug against the stack.
2. Verify copy settings: On the printer’s control panel, confirm that the copy function is set to “Letter” and not another size like A4.
3. Reset paper size defaults:  Kindly go into the settings menu and reselect “Letter.”
4. Clean and reload paper: Remove the paper, rearrange to prevent sheets from sticking, and reload it carefully.
5. Restart the printer: Power off the printer, wait 30 seconds, and turn it back on to clear any temporary glitches.

I hope this helps.