Adobe AEM Error Resolution
De Basef
Unable to validate node types since project wknd-sites-guide.ui.apps is not associated with a server or the server is not started
This error occurs at Eclipse IDE. To fix this:
1) Right+Click the wknd-sites-guide.ui.apps project in the Project explorer;
2) Open Properties > Project Facets;
3) Uncheck Dynamic Web Module.
This should resolve the error.