Restore access to a SQL endpoint
An inaccessible endpoint can fail before SQL is received. Test from the affected client host and keep the exact address, port and error. A successful connection from localhost does not prove that a remote application can reach the same listener.
Find the failing layer
Check that the hostname resolves to the expected destination and that the configured native or HTTP port is reachable. Confirm listen_host and any command-line address override on the server. HTTP is optional and is disabled when http_port is omitted.
For HTTP, test /ping before an authenticated query. A 401 response indicates credential failure. A 403 can indicate an Origin/Host restriction. A 503 can indicate admission or locking pressure. Capture the query identifier and exception code when a SQL response includes them.
Avoid unrelated changes
Do not rotate credentials to fix a refused TCP connection or raise query memory limits to fix DNS. Check each stage independently. Configuration-file edits require a restart, so verify the file path used by the running process before applying a change.
There is no hosted account state or recovery console in the documented Coordinator DB interface. Use the deployment's process and network tools for a stopped host or blocked route.
See HTTP status codes, configuration files and connection limits.