Moving index page to root causes Redirect Error

New problem:
I have managed to incorporate WP in my design (i have made a theme), which seems to be working nicely:
https://zetterstrand.com/eventz/
(eventz is my blog directory)
Even category templats work and stuff
https://zetterstrand.com/eventz/category/events/

Now i just want to put the blog at the root dir, so I move the /eventz/index.php to the root, and add configure it to match my blog dir (./eventz/wp-blog-header.php’)

see code:

<?php
/**
 * Front to the WordPress application. This file doesn't do anything, but loads
 * wp-blog-header.php which does and tells WordPress to load the theme.
 *
 * @package WordPress
 */

/**
 * Tells WordPress to load the WordPress theme and output it.
 *
 * @var bool
 */

define('WP_USE_THEMES', true);
/** Loads the WordPress Environment and Template */
require('./eventz/wp-blog-header.php');
?>

This also works fine
https://zetterstrand.com/

Yhat is, until I change the General settings Blog address to https://zetterstrand.com/ instead of
https://zetterstrand.com/

then I get a redirect error

Do you know what it could be?