I am cloning a repo of a Laravel project. I clone the repo and do php artisan key: generate which correctly sets the keys in .env. However when the app makes an external API request, it fails with the error

openssl_seal(): not a public key (1th member of pubkeys)

I have checked and the env('API_KEY') and 'API_URL' variables are correct.

public static function request(string $url, $data = []): Response
{
    //This is where the code fails
    $encrypt_result = self::encrypt($data, env('API_KEY'));

    return Http::asForm()->post(env('API_URL') . $url, [
        'key' => env('API_KEY'),
        'hash' => $encrypt_result['hash'],
        'e_key' => $encrypt_result['key']
    ]);
}

public static function encrypt(array $data, string $public_key): array
{
    //This is where the code fails
    openssl_seal(json_encode($data), $encrypted, $e_keys, [base64_decode($public_key)]);

    return [
        'hash' => base64_encode($encrypted),
        'key' => base64_encode($e_keys[0])
    ];
}

I have previously seen questions that attribute this to an error with XAMPP, and I was using XAMPP on Windows though have subsequently replaced it with Wampserver and the issue persists.

While using Linux on this project fulltime is not viable, I will be testing it later.

Is there anything simple I might be overlooking?