Small "powder room" with beat looking vinyl floor covering.

We got a box of sticky-tiles at Home Depot.
Scrubbed and rinsed the old surface.
Waited a weekend for it to dry,
then put down the new tiles.

A few weeks later, the tiles are lifting.
????

Anything special I should've done to the old covering
to make the new tiles adhere better ?
I hesitate running a sander over the floor.....

For what its worth, the box says "Made in China"
( maybe they haven't mastered the concept of sticky-tiles? )


rj