A Microsoft file hosting and synchronization service.
Same error. I not only can't search the contents of files, search files names in the web-version of OneDrive.com doesn't work.
The message I got from MS was "According to our dev team, they are working on the problem, but you can still search your OneDrive files using your computer with File Explorer or Finder"
However, that doesn't work either. My Win10 PC is fully indexing my OneDrive folder. I have the normal mix of PDFs, DOCs, TXT files. I've rebuilt the index and even turned on "Enhanced Searching" in the Windows Search setting. I still cannot find content within a PDF using Win10 search.