Because this is not an official addon hosted on the Stremio repository, you must download it from third-party repositories (like Stremio Community Addons). While the code is generally open-source, always be cautious about where you download addon repositories.
This is a seeding issue. Pause the video for 30-60 seconds to allow buffer accumulation. Or, switch to a file with a higher seed count (look for the "seeders" number in the stream list). popcorn time stremio addon