I also talked with my hosting provider. Below is their reply:
“As per checking, I found that the issue is caused by the WordPress SEO plugin that was installed whereby I have renamed the said plugin folder to disable it and your website is accessible now.
In this case, kindly liaise with your web developer or the plugin support as it seems that the plugin is unable to load a certain defined class as per below:
An error of type E_ERROR was caused in line 476 of the file /home/mrclean1/public_html/wp-content/plugins/wordpress-seo/wp-seo-main.php. Error message: Uncaught Error: Class ‘WPSEO_Register_Capabilities’ not found in /home/mrclean1/public_html/wp-content/plugins/wordpress-seo/wp-seo-main.php:476 “