Question: I have a fresh install of SugarCRM CE of Version 6.5.16 (Build 1082).

I'm having some issues setting up the SMTP server details in the admin panel. I've tried using the SMTP settings of my domain and also a gmail account and I get the same on-screen error message every time, 'Error:The following From address failed:' 

In the diagnostic log, it reads 

```
SMTP -> ERROR: Failed to connect to server. Code: 0 Reply: Unable to find the socket transport "ssl" - did you forget to enable it when you configured PHP? 
SugarPHPMailer encountered an error: The following From address failed: username@gmail.com

```

If anyone has experienced a similar issue I'd love to know how you fixed it

Thanks in advance

Answer: 
That error message is most likely related to SugarCRM/PHP and the webserver not having access to SSL-enabled email hosts. Depending on your system, you may be missing the `libssl` (`libssl1.0.0`) package or `openssl` altogether. 

If your system is old enough, SSL support may even be compiled and packaged seperately. Older Debian and Ubuntu systems called it `php5-ssl` if I recall correctly. But for the past few years, SSL support has been built in to the core PHP module.
In our case, the Antivirus mail shield was blocking the communication to the SMTP server. We disabled the mail shield and got it working.