406 Not Acceptable
An appropriate representation of the requested resource /articles/article/replace-into-vs-insert-into-on-duplicate-key-update-mysql could not be found on this server.
Interestingly, after a lot of (trial-and-error), I found that the word "insert" was the culprit !
When I removed "insert" from the URL seemed to redirect perfectly !
Still do not know the exact issue but will update here once I get to the root of the problem.
Edit 1: Intrestingly, this article with word "insert" in it did not raised 406 Error !
Edit 2: The problem was that my hosting provider had blocked the URL with "insert-into" in URL !
I got the URL whitelisted and mysql-difference-between-replace-into-insert-into-on-duplicate-key-update is resolving fine.