Problem with after-submission page

Hello

When a post is submitted at diarypal.co.uk, the text we wrote just disappears and we just see a blank form.

I’m also using WPUF on another site, diarypal.com, and on this site when the author clicks ‘Submit’, it shows the post they have just written.

I’d like diarypal.co.uk to do what diarypal.com is doing, but not sure how to do it. It is the same plugin and the same WP version, so I’m wondering why it’s behaving differently.

Any help will be appreciated, though I’m hoping it will not involved editing files.

Thank you.

https://wordpress.org/plugins/wp-user-frontend/