Laravel 5 POST routes to index instead of store

The problem was caused by a trailing / being added to the URL. So, instead of using this URL:

mydomain.com/api/v1/messages/

I tried with this one:

mydomain.com/api/v1/messages

and it worked.

I discovered it by taking a look at the server's log. That is how I discovered that POST requests to the URL messages/ were redirected.