Message E-91. When I turn the printer on I immediately get a picture of a spanner and code E-91.

Question

When I turn the printer on I immediately get a picture of a spanner and code E-91. What does this mean and how can I get past it? Help please

I have the same problem.I was performing a print head clean and nozzle check when the error first showed on the small screen on the printer. I have tried turning the printer off and leaving it to rest but the moment I turn the printer back on, the E-91 message shows next to a red circle with a cross in it and there is a picture of a spanner below.How can I fix the problem?