URL redirect works for once but when I refresh the page it doesn't work

I'm trying to redirect my reading list into a bookshop account.

I went through all of the steps - disabled the old URL and typed in everything right and it works when I first go to the page. But when I retype the (new) URL it says "We couldn't find the page you were looking for." etc. Then if I try a few minutes later it works again. Though it's not very trustworthy since I expect my URLs to work every time I try to reach them. Any ideas?

This is the link: https://www.wearecuriousfoxes.com/bookshop

What is your site url?