Board Thread:Support Requests - Getting Technical/@comment-15745114-20200525204515/@comment-9605025-20200526211625

Special:Upload does not support uploading from a URL. On legacy platform, URL uploading is supported via the in-editor tools. However, this is not the case on UCP. On UCP, you must use the "add video" button found in the upper-right corner of Special:NewFiles.