4 Plus actual build volume

Just ordered the Qidi 4 plus and in the mean time downloaded both Orca slicer and the Qidi studio as I wanted to confirm I could print a large print which s 298x292x80mm. Uploading the stl onto both slicers and it is coming up with an error stating it's too close to exclusion area.I would of hoped that as the build volume is advertised as 305x305 this error should not be coming up. So is there something I am missing? Is there a way of getting this to print or is the true build volume not 305x305?

From the pic it looks like two sides slope outwards, if this is the case and the measurements at the top exceed the build volume, then the print will not work.

The measurements are based from the top. In the preview model there are white corner outlines showing the overall area. It is tight but I would still expect it to print. I put it into fusion 360 just to check again.