Occasionally, extensive formatting will prevent the uploader from working. This issue is not very common, though, and your document should be checked for images/tables of contents if you are having issues, as this can increase the file size and cause issues.
We've recently updated our error messages to provide more specific information on why your document isn't uploading. Please make any corrections mentioned in the error message, to help your story upload.
If you still cannot upload your document, feel free to use the contact button at the top of this page to reach our support team!