Laravel email with queue 550 error (too many emails per second)

Question

Our emails are failing to send using Laravel with a Redis Queue.

The code that triggers the error is this: ->onQueue('emails')

$job = (new SendNewEmail($sender, $recipients))->onQueue('emails');
$job_result = $this->dispatch($job);

In combination with this in the job:

use InteractsWithQueue;

Our error message is:

Feb 09 17:15:57 laravel: message repeated 7947 times: [ production.ERROR: exception 'Swift_TransportException' with message 'Expected response code 354 but got code "550", with message "550 5.7.0 Requested action not taken: too many emails per second "' in /home/laravel/app/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php:383 Stack trace: #0 /home/laravel/app/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php(281): 

Our error only happens using Sendgrid and not Mailtrap, which spoofs emailing sending. I've talked with Sendgrid and the emails never touched their servers and their service was fully active when my error occurred. So, the error appears to be on my end.

Any thoughts?

Answer 1

Seems like only Mailtrap sends this error, so either open another account or upgrade to a paid plan.

Answer 2

I finally figured out how to set up the entire Laravel app to throttle mail based on a config.

In the boot() function of AppServiceProvider,

$throttleRate = config('mail.throttleToMessagesPerMin');
if ($throttleRate) {
    $throttlerPlugin = new \Swift_Plugins_ThrottlerPlugin($throttleRate, \Swift_Plugins_ThrottlerPlugin::MESSAGES_PER_MINUTE);
    Mail::getSwiftMailer()->registerPlugin($throttlerPlugin);
}

In config/mail.php, add this line:

'throttleToMessagesPerMin' => env('MAIL_THROTTLE_TO_MESSAGES_PER_MIN', null), //https://mailtrap.io has a rate limit of 2 emails/sec per inbox, but consider being even more conservative.

In your .env files, add a line like:

MAIL_THROTTLE_TO_MESSAGES_PER_MIN=50

The only problem is that it doesn't seem to affect mail sent via the later() function if QUEUE_DRIVER=sync.

Answer 3

Maybe you should make sure it was really sent via Sendgrid and not mailtrap. Their hard rate limit seems currently to be 3k requests per second against 3 requests per second for mailtrap on free plan :)

Answer 4

For debugging only!
If you don't expect more then 5 emails and don't have the option to change mailtrap, try:

foreach ($emails as $email) {
    ...
    Mail::send(... $email);                                                                      
    if(env('MAIL_HOST', false) == 'smtp.mailtrap.io'){
        sleep(1); //use usleep(500000) for half a second or less
    }
}

Using sleep() is a really bad practice. In theory this code should only execute in test environment or in debug mode.

Answer 5

I achieved this on Laravel v5.8 by setting the Authentication routes manually. The routes are located on the file routes\web.php. Below are the routes that needs to be added to that file:

Auth::routes();

Route::get('email/verify', 'Auth\VerificationController@show')->name('verification.notice');
Route::get('email/verify/{id}', 'Auth\VerificationController@verify')->name('verification.verify');

Route::group(['middleware' => 'throttle:1,1'], function(){
    Route::get('email/resend', 'Auth\VerificationController@resend')->name('verification.resend');
});

Explanation:

• Do not pass any parameter to the route Auth::routes(); to let configure the authentication routes manually.
• Wrap the route email/resend inside a Route::group with the middleware throttle:1,1 (the two numbers represents the max retry attempts and the time in minutes for those max retries)

I also removed a line of code in the file app\Http\Controllers\Auth\VerificationController.php in the __construct function.

I removed this:

$this->middleware('throttle:6,1')->only('verify', 'resend');

Answer 6

You need to rate limit emails queue.

The "official" way is to setup Redis queue driver. But it's hard and time consuming.

So I wrote custom queue worker mxl/laravel-queue-rate-limit that uses Illuminate\Cache\RateLimiter to rate limit job execution (the same one that used internally by Laravel to rate limit HTTP requests).

In config/queue.php specify rate limit for emails queue (for example 2 emails per second):

'rateLimit' => [
    'emails' => [
        'allows' => 2,
        'every' => 1
    ]
]

And run worker for this queue:

$ php artisan queue:work --queue emails