Canon FAX-L600

I have bought a Canon fax having model L-600. It seems technically being
very close to HP LJ II/III.
Anyways, it blinks red light and says something to add paper (sorry it is
not set to English menu)
I guess it is "SUPPLY REC PAPER".

However I have plenty of paper in front tray and it works thought okay,
takes copies etc. Left side tray is missing unfortunately.
I hope it is not because of missing tray ? Could it be similar than density
board condensator causing errors in LJ IIp/IIIp ?

So, anything to do to remove error ?!