I don't know if this is specifically a LiteSpeed issue or not, but I figure if post here you can help me narrow the search. My server is running LiteSpeed 4.2.1, RHEL 6, PHP 5.3.21. Over the past few weeks we've been having an intermittent problem with sending email from the site. This is affecting at least 2 different CMS platforms, both using the Zend Mail script. The sites are connecting to different SMTP servers, so I've ruled out the SMTP servers, CMS software and I'm down to either LiteSpeed or an OS problem. Here's the error message: Mail Exception Occurred. Unable to send mail: Could not open socket Some reports of this problem suggest increasing the open file limit as a solution, but that didn't help (and the error occurs even at low traffic hours). Any suggestions on possible LiteSpeed tweaks that could be related, or is this completely unrelated?