sendgrid php attachments

<?php

// If you are using Composer
require 'vendor/autoload.php';

use SendGrid\Mail;

$apiKey = getenv('SENDGRID_API_KEY');
$sg = new \SendGrid($apiKey);

$email = new SendGrid\Email("Me", "[email protected]");

$mail = new SendGrid\Mail();
$mail->setFrom($email);
$mail->setSubject("Attachment Test");
$p = new \SendGrid\Personalization();
$p->addTo($email);
$c = new \SendGrid\Content("text/plain", "Hi");
$mail->addPersonalization($p);
$mail->addContent($c);

$att1 = new \SendGrid\Attachment();
$att1->setContent( file_get_contents("test_files/1/1.txt") );
$att1->setType("text/plain");
$att1->setFilename("1.txt");
$att1->setDisposition("attachment");
$mail->addAttachment( $att1 );

$att2 = new \SendGrid\Attachment();
$att2->setContent( file_get_contents("test_files/2/1.txt") );
$att2->setType("text/plain");
$att2->setFilename("1.txt");
$att2->setDisposition("attachment");
$mail->addAttachment( $att2 );

$response = $sg->client->mail()->send()->post($mail);

echo $response->statusCode() . "\n";
echo json_encode( json_decode($response->body()), JSON_PRETTY_PRINT) . "\n";
var_dump($response->headers());

I had the same error response.
I fixed this by encoding the file first to base64:

$att1 = new SendGrid\Attachment();
$att1->setContent(base64_encode(file_get_contents("photo.jpg")));
$att1->setType("image/jpeg");
$att1->setFilename("photo.jpg");
$att1->setDisposition("attachment");
$mail->addAttachment( $att1 );

@Barendm worked like a charm. Thanks!

@Barendm Thanks works very fine