When you get this error trying to send emails in PhotoStore 4 it usually means the SMTP you setup requires ssl. A popular example is using gmail smtp, they tell you to enter:
smtp.gmail.com for the server.
However in PhotoStore 4 (php based) you will need to specify that this requires SSL, so type it like:
This will work on any system that requires SSL login to email system.
Just put ssl:// before the smpt server name.