Something strange with the "Add to Cart" button

Hello!
In VirtueMart Global configuration the option "Shop is offline?" is unchecked!
When a client is logged in and press "Add to Cart" button nothing happened!
In order to activate this button I have to enter backend with Administration login, go to Components>>VirtueMart>>Products and click on "List Categories". Then again "Joomla! Administration Login" appears. I have to login again and then the "Add to Cart" button works properly!!!
What is the problem?

Thank you and Best Regards!!!

Did you install template using HotStart method? If no, something is probably misconfigured in VM. Please send link.