smtp email settings

Hi All, I am new to SuiteCRM and this forum so please bear with me…
I installed the package on my webserver and all seems to be OK. However, I cannot send email.
I have entered the neccessary data on the smtp email page, my email provider, my name, my reply address ports, username and password. I get an errormessage that says:

Fehler:The following From address failed: stelzen@oakleaf-creativity.de

This address is valid and can be accessed via webmail and Outlook.
SMTP port is 465, TLS is activated

any comment or help is greatly appreciated…

Piet Koenekoop