I know this is old, but I just wanted to add a comment to detail how to customize the maximum file size , in case someone looks at this in the future:
In your site_config.json file, add the following:
"max_file_size": 52428800,
where the number is the maximum file size in bytes (this shows 50MB).
There could be other issues with doing very large files, but this can raise the limit from the current 10MB.