A blueprint is invalid if the connection between each blueprint group is broken. If a blueprint is invalid, this page will display information about the blueprint groups that are not connected properly. Note that you have to be the owner of the blueprint or need to have at least Organization Manager rights to edit blueprints.

Click the element from the first group, it should open the element page. Go to the [Blueprint Element Connections] section to fix the connections.

Click here to learn how Blueprint Connections work