“NEXT” post button not working

Hi, I had to manually resort some posts from 22.12.2019 to 07.01.2020 since my daily posts have not been posting in chronological order since the first date mentioned in one of my WordPress forums. Now, there should not be a “NEXT” post when you open the last post for obvious reasons, but I do have one and it takes me to a post written a few weeks ago. How do I fix this?