General: Not able to access to Synology NAS

Applies to: Existing Synology NAS installations, including supported DSM 7.3 systems. This is an initial network-access check; a login, storage or hardware fault may need a different assessment.

Check and resolve

1. Check the Power LED and the expected startup behaviour for the exact NAS model. If it is off, inspect the power connection and adapter indication without opening the unit. If startup never completes or an alarm occurs, record the LED/buzzer behaviour and seek advice rather than repeatedly power-cycling it.
2. Check the NAS Ethernet cable and the connected switch/router port. Compare with a known-working cable or approved port, keeping the existing network design in mind. Link-light behaviour varies by model; an LED alone does not establish that DSM is reachable.
3. Use an authorised computer on the same local network and subnet as the NAS. Guest Wi-Fi, client isolation, a different VLAN or a VPN can prevent discovery. Synology Assistant uses local broadcasts and cannot discover a NAS across a routed subnet or VPN.
4. Open the installed Synology Assistant utility and search. Match the model, server name and hardware address to the intended NAS, then note its current IP address and status. After a router replacement, the address may differ from an old bookmark.
5. If the status is Ready, open the administrator's established DSM HTTPS address using its configured port. The default HTTPS port is 5001, but an administrator may have changed it. Try another current browser; if a certificate warning appears, confirm the intended hostname and certificate rather than bypassing an unexplained warning.
6. If the NAS address is reachable but DSM is not, have the network administrator check the intended service port, local firewall rules and any address reservation. Do not open Internet-facing ports or disable the whole firewall to resolve a local-access problem.

Check the result

Confirm that the intended DSM sign-in page loads, then sign in with your own authorised account and check the expected shared folders. Reaching a sign-in page alone does not verify storage health.

Need help?

Submit Ticket with the NAS model, LED/buzzer pattern, Assistant status, exact error and any recent router/network change. Tell us whether a usable backup exists. Hide serial numbers, account details and private addresses from public screenshots.