System Error after searching

I get “System Error” message everytime I search something on a search page (localhost:8080) and also when I click session ID in crawling information.

Could you please tell me where to look in the logs to find what are causing these problems?

Thank you in advance.

Check …Exception in log files.

Got it. Thank you for your time!
I still couldn’t find what was causing this problem but I don’t get “System Error” anymore.
Maybe it has something to do with searching while crawling…