Error 404 when opening a post

When I’ve written a post and I’ve published it, I can see it on my site, the homepage. (http://thelovelynotebook.com/)

However, when I try to open a specific post I get an error 404. It says that the link doesn’t exist.

I’ve tried to save the permalinks a few times in “settings”, but that doesn’t seem to help. I’ve written different post, to see if something changes, but it doesn’t..

I’m hoping someone can help me with my problem!