Error creating bucket – Internal Server Error

You will need to enable WP_DEBUG_LOG to see what’s going on. Please add the following to your wp-config.php file:

define( 'WP_DEBUG', true );
define( 'WP_DEBUG_DISPLAY', false );
define( 'WP_DEBUG_LOG', true );

See https://codex.www.ads-software.com/Debugging_in_WordPress#WP_DEBUG_LOG for more information.

If you then try creating the bucket again it should populate the wp-content/debug.log file.