Ack! Sorry, I should have included an example without the rivers and roads. Two options, you can grab Fantasy Hex Tiles - Addon - Rivers and Roads v1 which is separate from the the base tile and use Tiled to locate the file, or, in the tiled file, just delete the Overlays and Rivers layers and it'll get rid of all the error boxes. (Note that cave entrances which are in the base png are on the overlay layer and will go away as well in this case)
Hopefully that helps? Let me know if you still have any issues <3