Pagination or Second Page Missing (and solution)

I came across the following issue: I started using the page tag to spread my content out among several pages. I found that the second page resulted in the custom 404 message. I checked and found that the end of my link structure (Options -> Permalinks) was
.../%postid%
That matches the structure of the second example on the permalinks page. The problem is that instead of getting a structure like
https://www.example.com/articles/1/2
for the second page of article 1, you get
https://www.example.com/articles/12
which is synonymous with asking for article 12.

A simple change of my structure code to:
.../%postid%/
fixed this problem. You just can’t leave the last forward slash off if you’re using multiple pages.