Republish error only in user account, works fine in admin

Hi All,

When an item has expired, i can republish it if i go in the backend through admin... but if a link is sent to email, or i try to republish in the user interface on frontend, It returns error...

Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator at webmaster@XXXXXXXXXX.co.uk to inform them of the time this error occurred, and the actions you performed just before this error.

More information about this error may be available in the server error log.

Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.


I have spoken to the server company and they have told me that it is a plug-in related issue
error log = [Wed Dec 27 22:54:16.277323 2017] [core:error] [pid 256724] End of script output before headers: republish.php

"This error indicates that there are some issues with the syntax of the republish.php file. Since this has to do with the syntax of your content, this is in the web development realm. I would recommend contacting the developer of the plugin for assistance with that error."

@Razor
If it is problem with republish.php, PHP itself will surely save error message refering to issue into it's logs.

Open your config.php & paste these lines there 
define('OSC_DEBUG', true) ;
define('OSC_DEBUG_LOG', true) ;
Try to generate error,
Now open folder oc-content &
Look into debug.log

You will find your answer there,   paste that log here.