An upload fails

Unsupported type — check the list in "Supported file types and sizes". Rename files with the wrong extension.

Too large — images up to 25 MB, fonts 10 MB, video 250 MB, documents 100 MB. Compress the file or export a smaller version.

Connection dropped — try again on a stable connection. Large videos take a while.

Upload took very long — upload permissions are valid for 30 minutes; start the upload again.

Uploads disabled — Settings → Environment shows whether file storage is configured.