It seemed this printer got 'stuck' somehow. I tested it on windows and
it was fine!

Somehow CUPS seemed to have a glitch. Accessories~>Manage print jobs
didn't permit me to delete the queue. I went to
http://localhost:631/printers as well. Then shame on me - took the
easy route out deleted the printers and installed again. All works
perfectly. So there wasn't a piece of paper jammed in there after all.