When filling soft or liquid food, do not overfill the bottle, the less air in the bottle, the longer the sealer will work and the sealing effect will be short.
Please check whether the mouth of the mason jar is dry and clean. If there is water or debris at the mouth of the bottle, the mason jar sealer will not be able to seal.
The mason jar vacuum sealer did not press into place and did not allow the mouth of the bottle to fully enter the sealer.
Mason jars don't match the lids.
Please note that frequent use may cause the silicone ring inside the Mason jar vacuum sealer to dislocate, resulting in seal failure, please manually adjust to the original position before use.
Make sure the electric vacuum sealer is centered and pressed firmly against the lid of the jar, Click the button to start the vacuum pump and wait about 40 seconds or more and the air can be evacuated to the seal. Clicking the button again closes the sealer.