Hi,
That is already how it works in HikaShop as it follows this setting of the Joomla user manager too for its own registration process.
If you don't see that message after the HikaShop registration, it's probably an issue with your Joomla template not displaying messages:
www.hikashop.com/support/documentation/6...issues.html#messages
To check on that you can do a registration via the HikaShop registration page while you temporarily switched to the default Joomla template. If this confirms that it comes from the template, I would recommend to check on what to do with your template provider support.