I don't think that the SFTP information will help. The migration might fail due to some connection timeout. Even if I would have the SFTP access, I would follow the same steps as you did, in order to do the migration.
There's still one thing we can try. Please generate a duplicator package as presented here https://wpml.org/faq/provide-supporters-copy-site/, and send it to me. This way I'll be able to create a copy of your website and check the issue with the string from the top of the page.
You can exclude the media files from the package, in order to keep it small.