Mug covering peeled off

Hello! First time heat pressing a mug here. I am using a Cuyi 6-in-1 heatpress with settings 180°C for 180 seconds as per the store instructions but the transparent plastic top layer of the mug peeled off together with the design after a couple of days using. Any insights that can help will be much appreciated!

Hello! First time heat pressing a mug here. I am using a Cuyi 6-in-1 heatpress with settings 180°C for 180 seconds as per the store instructions but the transparent plastic top layer of the mug peeled off together with the design after a couple of days using. Any insights that can help will be much appreciated!