doublex printing issues

Hello there,

I just got a brand new M12a and I am trying to print double-sided.  Following the instructions, I downloaded and installed the HP software. 

When I try to print, I get the option for 2-sided printing. (Figure 1). I select the option and hit print, so far everything is good, the printer prints the even pages of the document. After that, the printer gives an error message (Figure 2), and the orange light is flashing next to the triangle sign on top of the printer. For some reason, once I put the even printed pages back on the tray, the printer does not resume printing, and the orange light keeps flashing.

I have no idea how to go around that. In the past, I have used similar settings with different printers that had an additional button that was pressed once the printed pages were back in the tray, and this way the printing was resumed.

Can you please help?