Like the title says, the game marks some shrines that I think I never visited with a red cross, therefore it`s not possible to get the devotion points from those shrines, which means that I don`t have a chance to get all the devotion points available in this game.
I played today and when I began to play, two shrines were marked with a red cross. After some time I looked again on the map, I noticed that a third shrine was marked with a red cross. I did visit a shrine and I did clean it and I also got the devotion point for it.
Now I`m a bit confused, I know, that I cleaned all shrines I visited, can it be that those shrines were falsely marked with a red cross, although a did clean them, and got the point, or are there really shrines, that I cannot clean, due to the game thinking I failed to clean them?

Ah, okay, thanks a lot. I thought that the red cross means that I`ve failed to clean them. That means, I have to travel back and search the one at the very beginning of the game. :-)

Depending on what you have of the game you can find links to a list of the shrines with their requirements and where they appear on the various difficulties here.

https://forums.crateentertainment.com/t/spoiler-devotion-shrine-location-list/29194/181