Post Links Not Working!!!!

I am helping a friend with their website, and their links to their posts are not working. When you click on the link to the post for the full post, it produces 404 page not found error. They had transferred from one host to another, so I’m wondering if that could be the problem? Here is a link to the site:

https://www.eccbonus.org/

Can anyone help? They are using the Socrates theme as well. Please, any help would be greatly appreciated!!!