Great printing sub par adhesion.

We love sticker mule! Stickers mailers labels however, this one fell short. I'm not sure what I am doing wrong but the adhesive won't adhere to our boxes. I thought it stuck well but I had multiple customers say they recieved the packaged unsealed in places. I tried less water more time more water more time ex. Now we just tape over the packing water tape because I love how it came out but I'm paranoid of the lack of adhesion.