FYI: "Due to the massive popularity of the range search over searching by complete password hash, the significantly improved performance and the enhanced privacy controls, searching by hash will be discontinued on 1 June 2018."
I can't tell whether you knew this from the way your post is written, but this refers to searching by complete hash, not searching by the first 5 digits (aka range search).
Shown in API docs under "Pwned Passwords overview" and links to here: https://www.troyhunt.com/enhancing-pwned-passwords-privacy-b...