"could not translate host name": the endpoint string is wrong

"could not translate host name": diagnose and fix

Symptom

could not translate host name "[host]" to address (or the driver's DNS equivalent) on every connect attempt.

Cause (check in order)

1. The hostname was hand-typed or hand-edited: a typo, a missing segment, or a -pooler suffix added/removed wrongly.
2. The branch or endpoint was deleted or renamed; the string points at something that no longer exists.
3. Local DNS issues (rare; everything else resolves).

Confirm

1. nslookup [host] fails while other names resolve: it is the string, not your network.
2. Compare character-by-character against the Connect modal in the Console for the current branch.

Fix

• Copy the connection string fresh from the Console; do not reconstruct it by memory.
• If the branch was deleted, recreate it or repoint the app at the right branch.
• Pin connection strings in secret management so they cannot drift by hand-edit.

Verify

DNS resolves and psql connects with the exact string the app uses.

Neon's connection error docs (verified live 2026-09-26) list DNS resolution issues among resolved connection errors; the connect docs describe the Console constructing the string per branch/compute/database/role.