A family of Microsoft word processing software products for creating web, email, and print documents.
The error "We couldn't connect to the '{0}' catalog server for this add-on" indicates a problem reaching the add-in catalog, not a problem with a specific add-in.
From the available information, this error is documented in SharePoint/Excel Web App scenarios where the catalog URL or access path is incorrect, or where the user does not have access to the catalog that hosts the app. In those cases:
- The error appears when opening or using an app/add-in because the catalog server cannot be reached.
- Causes include an incorrect catalog URL or the user not having permission to the catalog.
- Resolutions in those environments involve correcting the catalog configuration or publishing the app to a store that the user can access.
In a personal Microsoft 365 scenario on Mac, this typically means the environment cannot properly reach or use the catalog that should supply Office Add-ins. Since the issue affects all add-ins in the browser versions and the desktop client is not showing the expected add-ins, the problem is with how the catalog or store is being reached, not with individual add-ins.
Because catalog connectivity and configuration are controlled on the service side, and the documented fixes in the provided material are specific to SharePoint/Office Web Apps Server 2013 and organizational app catalogs, the next step is to work with Microsoft support so they can verify catalog access and store configuration for the account and tenant.
References:
- "We couldn't connect to the catalog server for this app" error when you use Excel Web App to open a spreadsheet
- "Couldn't connect to the catalog server for this app" error when you click a guest link to a SharePoint Online item
- Troubleshoot user errors with Office Add-ins
- Errors when Office add-ins start
- Office Add-ins known issues