You get the following message in Promote options:
The selected web application needs at least one wildcard inclusion managed path to promote a subsite
When the promote options are loaded, the app checks your managed path to set your site as a site collection. If you don't have a managed path to set the site collection in, the operation will fail with this message. As an example, if you remove /sites from your environment, you would have a single root site collection from which the application couldn't promote the subsite(s).
You will have to define managed paths for your web application in SharePoint.