Ok, I have slate tile in entryway with grout about 1/4". I sealed floor only once about a year ago and need to seal again. I noticed that there is a crack between two tiles and also it looks like my german shep has raced around a few times too many and may have scraped a few chunks out. Nothing serious but I thought I could fill them in. I tried to add grout once before when sealant had just been done and the new grout did not stick. Is this because of the sealant? How to I fill in the crack and touch up the scrapes and make it stick??

I was going to get the tube of sanded calk that matches my grout for the space between the first row of tiles and the metal base of my front door. I figured the calk would be more flexible and stick to the metal as well as the tile. When I tried to use just grout it pulled away from the metal and looks bad.

Advise and thoughts please.