@stormgrass You have to go to wp-config.php and enable DEBUG mode to understand if plugin or theme is blocking.
Insinde wp-confing.php you will find:
define( 'WP_DEBUG', false );
define( 'WP_DEBUG_LOG', false );
define( 'WP_DEBUG_DISPLAY', false );
change to
define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', false );
define( 'WP_DEBUG_DISPLAY', true );
And you will see on the screen what is blocking your Wordpress instance.