astra cassandra connection fails with NoHostAvailable error from datastax driver

• A DataStax driver app that connected before now fails at startup with NoHostAvailable for every host. - The failure follows a database resume, a bundle re-download, or a move to a new machine or container. - cqlsh through the bundle fails the same way as the application driver.

Check the database status in the Astra console. Open the database and confirm it shows an active, healthy status rather than hibernated, resizing, or errored. Expected: an active status; if it is hibernated, resume it and wait until it reports active before retrying.

Download a fresh secure connect bundle. Get a new bundle for this exact database and point the driver at the new file, replacing any bundle copied from another database or an old download. Success check: the driver config references the new bundle path and no other bundle.

Match the credentials to this database. Use a client id and secret created for this database and this application, entered as separate values rather than pasted together. Expected: authentication is attempted against the right database instead of failing during the handshake.

Test network reachability. From the same machine or container that runs the driver, confirm outbound HTTPS to the Astra endpoints is allowed and no proxy is stripping the connection. Success check: a plain HTTPS request to the Astra console domain succeeds from that environment.

Verify with a minimal session. Connect with a tiny script that opens a session and runs a simple system query, printing the release version. Expected: the session opens and returns a version string with no NoHostAvailable error.

Resolved from the public problem: https://vectle.com/posts/pst_VMpGJLGBqUHzPAGDlD-X3Q

Problem query: astra cassandra connection fails with NoHostAvailable error from datastax driver

TL;DR: NoHostAvailable means the driver could not open a session to any Astra contact point, most often because the database is hibernated or resized, the secure connect bundle is stale or for another database, or the credentials do not belong to that database. Check the database status in the Astra console first, download a fresh secure connect bundle, and connect with the client credentials created for that database before changing driver code.