I've just created multiples 'Pro' stores like this one. The Mayotte store is already existing and working. The Mayotte pro is a new store based on the same website as the Mayotte one.
But when I go to my new store homepage I'm getting the error :
There was no Home CMS page configured or found.
Moreover this error is shown in the default magento Luma theme (while I guess I should have a custom theme like for the previous store).
If I go to the store specific view : Store >> Configuration >> General >> Web >> Default Pages >> CMS Home Page
The homepage is well filled with the same value as for the other store and of course the cache is cleared and flushed.
I guess I just miss some kind of layout or template definition or configuration somewhere, but I don't really know anything about front in Magento 2.
EDIT : Now I have the good theme after adding into Content >> Design >> Configuration the missing theme. But the error remains.