Trouble relinking clips

I am reopening a project in Resolve 12.5 I was working on only a couple days ago and now some of the clips say "media offline." I tried selecting them and right-clicking "relink selected clips" but they would not relink. I guided the search to the folder they were in, and after that it did a deep search, but still nothing, it just says it can't relink them. I think this is because a few days ago, apparently after the last time I edited, I made a new sub-folder within the folder they had already been in, and put the clips in the sub-folder (I'm somewhat new at video editing and forgot how important file location is!). But now I've tried moving them back where they were, but still it won't relink them. I know the problem is not with the original clips, they are fine--when I make a new project the clips play fine. Just this particular session can no longer connect to them for some reason.

Any ideas? Thanks in advance.

You can also right click clips and change the directory explicitly. But relinking should work unless your machine has lost the codec required to play this media back.