A device may retain a previously resolved address until its cache expires. If the service's address has changed, the old result can temporarily prevent connection. Many other faults look similar, so a cache reset is only one targeted comparison.
Start with the hostname
Check whether the service has supplied an updated server address. Avoid substituting an address from an unrelated website or another account. A correctly typed name matters more than repeatedly changing resolvers when the original URL is wrong.
Use the platform's controls
Reconnect the network or use documented cache-clearing steps for that operating system. Do not copy administrator commands from an unknown source. A router restart may affect the whole household and is unnecessary for every app-specific lookup problem.
Retest without repeated resets
After the device obtains a fresh result, attempt the same connection once and note the outcome. If it still fails, investigate the service address, account state or network rather than assuming that another cache clear will solve it.
