Fix a failed upload
If a video won't upload, walk through this checklist — most upload problems are fixed in under a minute.
1. Check the error message
Dubly shows specific messages for the most common upload failures:
Message you see | What to do |
"Only mp4 and mov files are accepted" | Your file isn't MP4 or MOV. Convert it to H.264 MP4 and try again. |
"File is too large. Maximum size is 5 GB" | Export a compressed H.264 MP4 at 10–15 Mbps — quality stays high, file shrinks. |
"Upload failed. Please try again" | Temporary network glitch. Retry the upload. |
"Failed to generate upload URL. Please try again" | Retry. If it keeps failing, contact support. |
If you're uploading via a YouTube link:
Message you see | What to do |
"YouTube URL is required" / "Please enter a valid YouTube URL" | Paste a |
"Video not found" | The video is private, deleted, or region-restricted. Make it public or unlisted, or upload the file directly. |
2. Confirm the basics
Before retrying, check the file:
Format: MP4 or MOV. Dubly doesn't accept MKV, WebM, AVI, or audio-only files.
Size: under 5 GB.
Has audio: the video must have a spoken audio track.
Not corrupted: try playing the file in QuickTime or VLC. If it won't play there, it won't upload. See Supported Input Formats for the full reference.
3. Try a fresh upload
The uploader doesn't support resume — if you refresh or the connection drops mid-upload, progress is lost and you have to start from zero. For large files over slow connections, make sure:
You're on a stable network (wired or solid Wi-Fi, not mobile data).
The browser tab stays open until the upload completes.
You have a fresh browser session — close and reopen if the tab has been open for hours.
4. Browser-specific checks
If the upload dialog doesn't open, the progress bar never moves, or the drag-and-drop zone doesn't react:
Update to the latest version of Chrome, Safari, Edge, or Firefox.
Disable browser extensions that intercept uploads (ad blockers, VPN extensions).
Try an incognito / private window.
Try a different browser once.
5. For YouTube links
If YouTube upload fails:
Copy the link directly from the video's address bar, not from a "Share" button (some share buttons add tracking parameters that break the parser).
Confirm the video is Public or Unlisted — Private videos cannot be accessed.
If the video has region restrictions or age restrictions, download it first and upload the file directly instead.
6. Still stuck?
Contact hello@dubly.ai with:
The exact error message (or screenshot)
The file size and format (or the YouTube URL)
The browser you're using
A rough timestamp when you tried We can check the server logs directly and get you unstuck.