Originally Posted by till
Your mail client did not authenticate itself with smtp-auth. Please enable smtp authentication in the email client.
Using Thunderbird I've tried all 4 authentication options...
Security and Authentication
Use name and password is enabled. (using email address as user)
Use secure connection has 4 options and I've tried all 4.
TLS if available
TLS option gives "Unable to connect to SMTP server myserver via STARTTLS since it doesn't support EHLO.
using TLS if available or NO gives the relay error I quoted above.