It is a common error on websites, yet it is one of the most annoying for web developers and system administrators. The dreaded 500 “Internet Server Error” has plagued webmasters for years. Sometimes, it is very easy to fix, but it may be difficult to find out what the problem actually is because it is such a vague error. Nevertheless, if you know where to look, you may be able to remedy the situation quickly and easily.
A few possible causes could be:
Incorrect permissions on your scripts. If the scripts are not executable, they will not run. If you have installed a third-party web application, check the documentation for correct permissions
Incorrect settings in htaccess – The server will load the contents of your .htaccess file before anything else, so if there is something wrong, your site will come to a screeching halt.
Bad code – This may be a bit more tedious, but if you have written your own scripts, you will need to go through them and check the syntax and look for any mistakes.
Once you narrow down the problem, you should be able to fix a 500 error relatively quickly, and your server and website will return to business as usual.