openai/codex · error · BuildCustomCaTransportError

Failed to register certificate #{certificate_index} from {}

Error message

Failed to register certificate #{certificate_index} from {} selected by {} in rustls root store: {source}. {hint}

What it means

Error "Failed to register certificate #{certificate_index} from {} selected by {} in rustls root store: {source}. {hint}" thrown in openai/codex.

Source

Thrown at codex-rs/http-client/src/custom_ca.rs:133

    /// Reqwest rejected the final client configuration after a custom CA bundle was loaded.
    #[error(
        "Failed to build HTTP client while using CA bundle from {} ({}): {source}",
        source_env,
        path.display()
    )]
    BuildClientWithCustomCa {
        source_env: &'static str,
        path: PathBuf,
        #[source]
        source: reqwest::Error,
    },

    /// Reqwest rejected the final client configuration while using only system roots.
    #[error("Failed to build HTTP client while using system root certificates: {0}")]
    BuildClientWithSystemRoots(#[source] reqwest::Error),

    /// One parsed certificate block could not be registered with the websocket TLS root store.
    #[error(
        "Failed to register certificate #{certificate_index} from {} selected by {} in rustls root store: {source}. {hint}",
        path.display(),
        source_env,
        hint = CA_CERT_HINT
    )]
    RegisterRustlsCertificate {
        source_env: &'static str,
        path: PathBuf,
        certificate_index: usize,
        source: rustls::Error,
    },
}

impl From<BuildCustomCaTransportError> for io::Error {
    fn from(error: BuildCustomCaTransportError) -> Self {
        match error {
            BuildCustomCaTransportError::ReadCaFile { ref source, .. } => {
                io::Error::new(source.kind(), error)

View on GitHub (pinned to 339751715c)

When it happens

Trigger: Thrown at codex-rs/http-client/src/custom_ca.rs:133 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• SSL/TLS and certificate errors — how TLS handshakes and certificate validation fail.

AI-assisted analysis of openai/codex@339751715c (2026-08-25). Data as JSON: /api/errors/44844b3bc54e605f. Report an issue: GitHub.