didn't know about docdrop, I thought it was similar to Annotate.tv but I got: "Our video annotation capability works for YouTube videos that have either human or machine-generated transcripts.". That's not a requisite on Annotate.
You need to choose a YT video that has a auto-generated transcript. About 80%+ videos do I think. Choose another one. Docdrop+Hypothesis only works on transcripts-- it's not a timecode video annotator.