DDNS page status: "Failed to connect to the server".

• Synology DDNS Pre-checks
• For DDNS offered by other service providers

Synology DDNS Pre-checks

1. Check if your Synology device is properly connected to the Internet to rule out a network connection issues. Make sure that you have properly configured the following settings.
   DSM: Go to Control Panel > Network > Network Interface.
   SRM: Go to Network Center > Status.
2. Temporarily assign "8.8.8.8" to the Preferred DNS Server and "8.8.4.4" to the Alternative DNS Server.¹
   DSM: Go to Control Panel > Network > General > Manually configure DNS server.
   SRM: Go to Network Center > Internet >  Connection > Manually configure DNS server.
3. Temporarily disable IPv6 connection.
   DSM: Go to Control Panel > Network > Network Interface. Select your network interface and click Edit. Under IPv6, set IPv6 setup to Off.
   SRM: Go to Network Center > Internet > Connection > IPv6 Setup. Set IPv6 setup to Off.
4. If your Synology device is joined to a domain, make sure the DNS server of the domain can resolve the websites required by DDNS and External IP Analyzer. For domains created by Synology Directory Server, you can Enable resolution service and Enable forwarders in the DNS Server package. Please refer to this article for more information.
5. Select a NTP server and click Update Now to make sure that the time shown on your Synology device is correct.
   DSM: Go to Control Panel > Regional Options > Time > Synchronize with NTP server.
   SRM: Go to Control Panel > System > Regional Options > Current Time.
6. If you have configured firewall settings or proxy servers in the network environment, make sure that the websites required by DDNS and External IP Analyzer are not blocked.

For DDNS offered by other service providers

1. Make sure the account credentials you entered are correct.
2. Contact the DDNS service provider for assistance.