When I was developing a SharePoint 2013 app I encountered the following error when I published the App package and tried to add the App to a site:
The specified application identifier [GUID] is invalid or does not exist.
The problem seems to be that the App itself is not registered (as safe?) in the SharePoint tenant. In this case I use SharePoint Online. To fix that issue navigate to your App catalogue site collection and manually open this page: “_layouts/15/appregnew.aspx”
There you can register a new App with appropriate Client Id and Client Secret. Don’t forget to update your AppManifest.xml in your App and the Web.config when you are also using a seperate Web App project.
“…navigate to your App catalogue site collection…”
No clue where that is. Nothing by that name is visible on the SharePoint site.
Hi Alan,
you can find or create your App Catalogue Site Collection as described in this article: https://support.office.com/en-us/article/Use-the-App-Catalog-to-make-custom-business-apps-available-for-your-SharePoint-Online-environment-0B6AB336-8B83-423F-A06B-BCC52861CBA0