This typically happens on older Windows XP machines but can affect newer Windows versions as well that have not been updated to the latest patches. You may see an error similar to the screen shot below, indicating that the client is not able to communicate to the server.
First verify that there is not a firewall or other network device causing the problem by pinging the service host in the configuration. If the host resolves but the issue persists, next check the .NET framework version that is installed. Due to recent security updates on our servers, the .NET 4 Client profile does not support the protocol change of the latest openSSL libraries anymore. For Windows XP systems, Microsoft updated the .NET 4 Extended versions with the security fixes, but every windows version above will need .NET 4.5 Framework installed as minimum requirement. Otherwise, you will see the sync request time out.
.NET 4.5 framework, if for any reason that is not possible on older
Windows XP systems you must install the updated .NET 4 extended
version containing the security fixes.
MS link to .net 4 installer complete with extended profiles
MS link to .net 4.5
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