SMTP Error (by using sendemail)

[almightya]

Hello,

i want to use the command-line-tool "sendemail" to send mails, such as log-files, ... to recipients.
I can only send mails to the same mail-account (from/to) in Plesk, but a Mail-Delivery to external
recipients fails. The error appears by the smtp/sasl-authentification.

Error: 535 5.7.8 -> Error: authentification failed: bad protocol / cancel

How can i solve this problem?

There are no Problems with the Mail-Delivery in Outlook, ...
(equal if unencrypted, encrypted, SSL/TLS, Port 25, 465, 587)

Hope of your help, thanks.