Calibre ebook sharing

[Elsa]

Hello. I'm new to this forum and only recently started to use Calibre. I'm helping a friend create an ebook. To experiment with book sharing I uploaded a short story of my own to Calibre and attempted (numerous times) to send it via email. It all seems so simple but try as I might all attempts fail. I've opened a gmx email account and tested it with a message and that's fine but not when I then try to send the ebook. Any help would be greatly appreciated.