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Regarding registration of the application see also last section of SharePointof SharePoint: Deploy Add-in package to the App Catalog (v 1.7) requiring requiring to register the app with the correct Client ID, Confluence host and provider url.
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- Missing DNS entry for app web host name pointing to the SharePoint farm - see DNS part of Preparing the SharePoint Add-in Infrastructure (v 1.7)
- Certificate not accepted by browser, e.g. missing in the certificate of the SharePoint farm - see HTTPS part of Preparing the SharePoint Add-in Infrastructure (v 1.7)
Checking assets library and loader file
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