My two cents: (I'm out of town had so e minor surgery and the hospital does not really allow an Portable IT infrastructure :-) )at the moment and no DXlab at hands).
But as far as I remember, besides the orientation ( portrait vs. landscape) make sure the label ( card? ) dimensions match both in qsl config AND in Dxlabs Printer config.
Initially I had problems with those settings, because The printer specifies height/width and Dxkeeper width/height ( or so) . Initially I got confused with that. But now, it works.
In addition, to prevent those naughty margin messages, I simply set the qsl config sizes slightly lower than the actual label size and order the program to ignore printer margins.
regards Peter, DK5DC
Typos are intentionally inserted by my Ipad
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ARRL VE & DXCC Field Checker
Editor CQDL Dxtra