How to enable email so we can send directly?
Settings → Obsolete features → Internal pdf generator - > enable
Then email will send the actual document not a link to login to your server
@ailebioline, @Patch addressed emailing PDFs. But perhaps you need more complete instructions about email in general. If so, read the Guide: Email transactions and reports | Manager.
Read the Guide about troubleshooting email. Follow all relevant links and instructions in the Guide.
Your hostname is almost assuredly wrong.