The central service starts and stops

Its log says why: %ProgramData%\Routes\Central\Logs on Windows, journalctl -u routes-central on Linux, or docker compose logs central.

In the log	Cause	Fix
Login failed for user …	SQL Server does not know the service’s account, or it may not create the database	Give the right login dbcreator (NT AUTHORITY\SYSTEM on the same server, DOMAIN\HOST$ from another): see The database.
A network-related … error	SQL Server’s name or instance is wrong, TCP/IP is off, or a firewall blocks it	Check the server name, enable TCP/IP, open the port.
needs PostgreSQL 18 or later	An older PostgreSQL	Upgrade, or use another server.
The connection string must name a database	No Database=	Add it.
The database’s schema is version …, newer than this build knows	An older build pointed at a newer database	Install the newer build, or use another database.
… would serve the console and node API over plain HTTP	No certificate and HttpsMode=Http not set, on a non-local address	Give it a certificate, remove the plain-HTTP address, or set HttpsMode (behind a TLS proxy only). See HTTPS.
Certificate … was not found in LocalMachine\My	The thumbprint is wrong, or the certificate was removed	Fix CertificateThumbprint.
Secrets cannot be encrypted on this server	The SecretProtection setting cannot be used (wrong account, missing file)	See Several central servers.
Development mode … only listens on this machine	DevelopmentUser is set on a real server	Remove it. Never use development mode in production.

While the database cannot be reached, the service keeps trying, and the console says the database is not ready. Nodes keep routing meanwhile.