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210 mm x 594 mm is as wide as A4 but as long as A2 size.
That's an eccentric size of paper. It may be the printer does not and can not support it. But tell me, before I pronounce a certain Answer to this question: What are you printing from, a Windows PC, or an Apple computer? and, printing from any particular program?
Let me know, by Reply To Expert, and I will advise you.
Does Apple's Photos program (or, iPhoto perhaps?) list that size?
If not, then what is the MAC OS X version on the computer, please? (apple menu, About This Mac, will show the 10.X version #.)