Your grass was too noisy and also too uniform around the edges!
Here, I did a quick edit to illustrate:

 From the chest, it looks like you're trying for too much complexity in your sprite! I redid your grass to be sparse tufts of longer grass on a uniform elongated checker pattern to create a simpler-looking and easier to make grass tile that can be tweaked to allow for more unique tiles to break up monotony and prevent the eye from figuring out where the tiles start. Hyper light drifter used this kind of technique a lot in more forested areas, if you want a good example of the concept!

For example, you could stick flowers on some tiles and a different grass pattern on others. Small rocks, bits of plantmatter, rubble and walkways, etc. Get creative, think about what would be in the area you want to portray!

Try to keep your art style unified too, if the characters are going to be reasonably simplistic/cartoony try to keep the level of detail on everything else about the same!*
(*Granted, I am reading this entirely off that chest design. Feel free to disregard this if the characters have a similarly high level of detail! If that's the case, I reccomend reducing your color count by a couple and simplifying the texture still as well as doing the above small-details work for more visual variety)

I couldn't tell where it tiled on my end, so I reccomend highly going over it yourself to make it work right with your dimensions.