Why does MP4 export fail or become unavailable?
MP4 export depends on browser encoding support, the selected resolution and available device resources. Keep the tab visible and try a shorter, lower-resolution export first. An 8K option does not mean every browser and computer can encode it.
Check the browser and settings
Use a browser with WebCodecs and a supported H.264 or H.265 encoder. The export dialog checks available options and identifies the selected codec. Reduce resolution if the requested size is unsupported; an HEVC file also needs a compatible player.
Try a smaller export
Save a project backup, close memory-heavy tabs, keep Modolly visible and export a short sequence. If it succeeds, increase duration or resolution one at a time. Plan limits still apply even when the hardware supports a larger output.
If the problem continues
Note the browser version, operating system, resolution, duration and visible error. Send those details to support@modolly.app. Do not send private screen recordings or project files unless you intend to share their contents.
Watch the related editor walkthrough.