If you choose ActiveUpdate server, ensure that the server has Internet connection and, if you are using a proxy server, test if Internet connection can be established using the proxy settings. For details, see Proxy for Apex One Server Updates.
If you choose a custom update source, set up the appropriate environment and update resources for this update source. Also ensure that there is a functional connection between the server computer and this update source. If you need assistance setting up an update source, contact your support provider.
The Apex One server uses component duplication when downloading components from the update source. See Apex One Server Component Duplication for details.