Question Class 'PHPMailer' not found in libraries/joomla/mail/mail.php on line 28

joey2509 wrote: just wanted to point out that it is a 500 error and not 505

I really should have paid more attention to the text, written in large font, shown in the image in the original message! :blush:

HTTP 500 Internal Server Errors are in a whole different basket to HTTP 505 Version Not Supported errors. In any event, it's an almost certain bet that these catastrophic errors are not caused by Kunena but they are caused by something interfering with Kunena in order to display information on a web page in response to something a user wants to do.

I suggest that you look at the following:

forum.joomla.org/viewtopic.php?p=2365264
forum.joomla.org/viewtopic.php?p=1843691

You should also check the settings in Global Configuration » Server » Mail Settings

Mailer
Mail from
From Name
Sendmail Path
SMTP Authentication
SMTP Security
SMTP Port
SMTP Username
SMTP Password
SMTP Host