A correctly functioning machine will cut proofgrade without issue, so you should probably get that sorted out first.
Support will ask you to print the Gift of Good Measure on the spare medium draftboard provided with the machine, using the default settings, and post pictures of the result from the front and back.
They might also ask for pictures of the optics, as seen here.
This information will let them determine if there is a problem with the machine that requires repair.