Step 1 :  Increase Vacuum Strength by pressing the load paper button so that the printer is ready to accept the media.  With the gap open, you will see a 3 stage vacuum icon. Press the up arrow button to increase it to the  highest level.   Reprint 

Step 2 : If step 1 does not resolve the marks, raise the platen gap by hitting Menu - Printer Setup - Platen Gap  - Increase platen one step up and reprint (ex. Standard increase to  High)