Why Am I Obtaining This Error Trying To Bind The Properties From An Angular Parent Component To A Child Component?

I am very new in Angular and I am finding some dificulties trying to add a component and use it into a project on which I am working on. I have a parent component view that contain

Solution 1:

Please make sure that for all the selectors that you are using, the components are declared in your module (or in one of the modules which this module has imported). The mail-detail-protocollo-sidebar is not a web-component, which indicates that the component has not been declared anywhere in the application.