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.
Any ideas? Thanks in advance.