Hi there,
Thank you for providing the login information. I double checked the website and found out these 2 errors:
The first error is related to the nonce verification. Wordpress does have a way to secure the access to the website with a unique stream of characters called SALT. That value can be set in the wp-config.php file of your Wordpress installation root.
There seems to be a problem regarding that and you need to change the SALT of your website and you will need to reset it. To do so kindly read the article below:
The second error is 500 Internal Server Error which can be caused by several reasons and the message does not give us enough information. You will need to contact your hosting service provider and ask them to check their error log and give you the actual error which is happening internally on the server so that we can have a better understanding of the problem.
The common problems which throw that error are:
- Bad file/folder permissions. To make sure the permissions are correct kindly read this article:
https://codex.wordpress.org/Changing_File_Permissions
- Bad settings for Cache plugins:
Sometimes cache plugins try to minify the assets of our theme which makes problems as we already do minify the assets. You will need to go to the plugin settings and exclude minifying of the theme related CSS and JS files or avoid using that specific plugin altogether.
- mod_security rule settings of the hosting service provider. You will need to contact your hosting service provider and ask them to exclude the Cornerstone URLs from their mod_security rules.
Hope I could tackle the most common possible causes that might be the reason Cornerstone is not showing on your website.
Thank you.