I made a new installation of Magento 2.2.3, everything is working just fine.
However, when I do pass an order this error msg shows up:
An error occurred on the server. Please try to place the order again.
when I checked the log, this is the detailed msg:
Registry key "sales_order_status_before" already exists {"exception":"[object] (RuntimeException(code: 0): Registry key \"sales_order_status_before\" already exists at public_html/vendor/magento/framework/Registry.php:51)"} []
and there's nothing on the internet about it!