Different errors obstruct the functioning of the WordPress website, and WordPress error 500 is one such error. However, there is no difficulty in solving internal server error. Perform according to the guidelines described below:
Raise the PHP limit of the website because often, PHP memory exhaustion is one of the causes of the internal server error.
Rename the existing .htaccess file which makes it disable then create the new one
Re-install the core WordPress files
Uninstall plugins one at a time to identify the incompatible one. Once you manage to detect the incompatible Plugin, remove it permanently from the WordPress website