7880 Paper sensor issue

After a considerable effort I have the 7880 up and running on k7 Inkt. Was looking very much forward to getting super BW prints.
Unfortunately the printer got very fussy about what kind of paper loaded.
Now all papers are rejected, roll, sheet, big or small.
I take it it’s the paper sensor? How can I solves this problem.

You can turn the “paper size” and “paper skew” sensors off right on the control panel of the printer.

best regards,