warning: SASL authentication failure:

[elitepilot]

Mar 12 16:34:23 server postfix/smtpd[734]: warning: SASL authentication failure: incorrect digest response
Mar 12 16:34:23 server postfix/smtpd[734]: warning: dslb-XXX-XXX-XXX-XXX.pools.arcor-ip.net[XX.XX.XX.XX]: SASL CRAM-MD5 authentication failed: authentication failure
Mar 12 16:34:24 server postfix/smtpd[734]: warning: SASL authentication failure: incorrect NTLM response
Mar 12 16:34:24 server postfix/smtpd[734]: warning: dslb-XXX-XXX-XXX-XXX.pools.arcor-ip.net[XX.XX.XX:XX]: SASL NTLM authentication failed: authentication failure

Anyone know what these error means?

[joximu]

Something with SMTP and SMTP Auth/sasl...
I don't know what exactly the error causes - but for me this is enough to know where to find more specific help.