Upon checking, your metadata.jsonl file format seems to be correct when validated using a JSON validator. Based on the error messages that you’ve received, it looks like it has something to do with the uri. In your .json file, you can try removing the documents with ID's 2-4 temporarily to help isolate the issue within your URIs. If there's no issue with id 1, then you can try id 2 next and so on.

Also, as mentioned in this documentation the maximum file size for Cloud Storage URIs is 2.5 MB for text-based formats, 200 MB for other formats which you can also check on your end.