php-aws | PHP classes for working with Amazon 's web services platform | AWS library

I'm trying to build and deploy my angular project with gitlab pipelines. There are two jobs. One for building the angular app and one for the deployment. My gitlab-ci.yml looks like this.

I'm trying to send 2K emails to my customers. I'm using Amazon SES to send the email using this library. When I try to send the email with the attachment, I'm getting SimpleEmailService::sendEmail(): 35 Process open FD table is full error. I just followed the instruction given in the readme file. And changed credentials only. Any help will be appreciated... :)

Edit

Almost 900 emails with the attachment sent successfully. But after that, it starts throwing the error.

The attachment is of type PDF.

Edit 2

The service team says that you are not closing the file descriptor after sending the mails. You need to close the file descriptor after the job is done. That way it wont exhaust the limit set on the number of FDs assigned

Here is the code I'm trying.

I'm Developing web Application that user can register by them self and log in after confirmation.i used AWS JavaScript for that it's working great.but since the access key is visible for everybody i planed to do it in Using PHP-AWS SDK.but why all the example aws providing foe EC2 or S3, i couldn't find any for cognito in php.can someone guide me or provide a basic example for this scenario..?