After update to 2.76 the plugin tries to connect to SMTP server port 25 by default, even if SSL is enabled and it should use port 465. This results to connection error:
If I specify port 465 manually, I get another error:
The only way I could get the plugin working was disabling SSL and changing port to 25. However, it is unclear does the plugin try to use STARTTLS with such settings, and is a connection secure or not.