I am unable to send messages using my outlook.com email account

I am facing a problem with my Outlook.com account… I am unable sending via SMTP… 
Error is:
“An attempt was made to access a socket in a way forbidden by its access permissions 65.55.176.126:587”

Receiving emails is no problem (IMAP).

I am using the following settings:

What to do?

Cheers,
Frank