I am running a Ultimaker 3 Extended. The specifications state a build volume of 8.5" x 8.5" x 11.8".
I have a part that is 5.25" x 7.5" x .28" or in mm it's 133.2mm x 190.5mm x 7mm .
When I upload the model into Cura 2.3 the size it reports is correct, however Cura reports it is unable to slice due to the size of the part.
I applied a raft adhesion to minimize foot print, but no luck.
I have reviewed settings, however have not found anything that looks helpful.
Cut and paste the link below to see a snap shot of my screen.