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If you have issues loading the Office Connector when using localhost, please try following the documentation at: https://docs.microsoft.com/en-us/office/troubleshoot/error-messages/cannot-open-add-in-from-localhost
To debug an Office Connector which has been successfully sideloaded but has different issues, please try following the documentation at: https://docs.microsoft.com/en-us/office/dev/add-ins/testing/debug-add-ins-using-f12-developer-tools-on-windows-10