/api/token 403 error on VPS, but works locally.

[KennethDev]

I'm developing a web application that uses the Authorization code OAuth flow. While testing it locally it works correctly. However, when I deploy it to a VPS hosted at OVH, I get a 403 error.

<h1>Error: Forbidden</h1>
<h2>Your client does not have permission to get URL <code>/api/token</code> from this server.</h2

I have another VPS (also with OVH) that it also works properly on, so I'm at a loss.