If you're using large format tiles you will need to use a thick-bed tile adhesive. A thick-bed tile adhesive will have 'filler's in it or a coarse sand to help it bond and cure correctly without shrinkage and cracking.
Using the wrong tile adhesive and tiling trowel for large format tiling can cause tiles to not be bonded and eventually become un-fixed.
Using the wrong tile adhesive and tiling trowel for large format tiling can cause tiles to not be bonded and eventually become un-fixed.