Possible causes of the machine not Vacuum Sealing:
Check for wrinkles in bag along Sealing Strip. To prevent wrinkles in the seal, gently stretch bag flat while inserting bag into Vacuum Channel.
Open unit and make sure Gaskets are inserted properly and there are no foreign objects, dirt or debris on the Upper or Lower Gasket
Latch has been left in OPERATE position: Gaskets may be compressed. Unlatch and allow 10 to 20 minutes for Gaskets to expand.
Make sure the accessory hose is not attached to accessory port.
Make sure the lid is latched down all the way. If the Latch does not catch the lid and bring it down, there will be a leak between the Gaskets.