An error 500 in the server can be an all-encompassing issue with the server that hosts the website.
In most cases it means that there's an problem or temporary glitch in the programming of the website.
There may be 4 to 5 reasons why this error causes .
A broken htaccess file or may be a permission error are most common causes.
Faulty third party plugins or themes and PHP memory limit is also important.
But there are many things we can do to fix it .
Some important tips are Refreshing the page,come back later ,delete your browser cookies.