error 500: FrontController.php:185

[HaCos]

Hello, sometimes when i navigatte within my store i receive error 500 pages for no reason. I enabled profiling and i mentioned that the error is caused because of FrontController.php on line 185:

$useSSL = ((isset($this->ssl) && $this->ssl && Configuration::get('PS_SSL_ENABLED')) || Tools::usingSecureMode()) ? true : false;

I have enabled ssl only for checkout pages. 

Does anyone has any clue?