Flex template _ SP page Builder

I purchased Flex template. After installation I created the home site with Sp Builder by connecting it to the menu item>home, but it gives me an error. (Oops… Page Not Found! We’re sorry, but the page you were looking for doesn’t exist. strpos(): Argument #1 ($haystack) must be of type string, stdClass given)

If, on the other hand, I create an article and connect it to the home page, there are no problems.
I also tried to install SP PAGE Builder again, but I have the same problem. What could be the problem?