thephpleague/flysystem · error · League\Flysystem\PhpseclibV2\UnableToLoadPrivateKey

Unable to load private key.

Error message

Unable to load private key.

What it means

Error "Unable to load private key." thrown in thephpleague/flysystem.

Source

Thrown at src/PhpseclibV2/SftpConnectionProvider.php:226

        }

        throw UnableToAuthenticate::withPrivateKey();
    }

    private function loadPrivateKey(): RSA
    {
        if ("---" !== substr($this->privateKey, 0, 3) && is_file($this->privateKey)) {
            $this->privateKey = file_get_contents($this->privateKey);
        }

        $key = new RSA();

        if ($this->passphrase !== null) {
            $key->setPassword($this->passphrase);
        }

        if ( ! $key->loadKey($this->privateKey)) {
            throw new UnableToLoadPrivateKey();
        }

        return $key;
    }

    private function authenticateWithAgent(SFTP $connection): void
    {
        $agent = new Agent();

        if ( ! $connection->login($this->username, $agent)) {
            throw UnableToAuthenticate::withSshAgent();
        }
    }
}

View on GitHub (pinned to b277b5dc3d)

When it happens

Trigger: Thrown at src/PhpseclibV2/SftpConnectionProvider.php:226 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of thephpleague/flysystem@b277b5dc3d (2026-08-17). Data as JSON: /api/errors/524d6356d30a1bf0. Report an issue: GitHub.