404

Hi, im really hoping someone can help me!
Whenever i click on a link to my actual post i get a 404 page…. Im quite the novice with word press so this may (and i hope) be something simple. below is a link to my blog if anyone knows the reason why, help would be appreciated

https://rebeccakdesigns.com/blog/

If you click on the heading of the post title instead of going to the post it goes to 404 this is the same with trying to send links to any post e.g through facebook