Contact Form 7 can't send attachment more than

问题:

Attachment is uploaded into server. But, unable to send attachment using contact form to email if file is larger than 6MB. Ajax is loading. I encounter the following errors:

 EMAIL DELIVERY ERROR: the plugin WP Mail SMTP v1.4.1 logged this error during the last time it tried to send an email:

Mailer: Gmail

Request Entity Too Large

Request Entity Too Large Error 413

Here is my setting:

I have increased the following in php.ini:

      
upload_max_filesize = 512M
post_max_size=512M
max_execution_time=600
max_input_time=600
memory_limit=1024M

CF7 file limit: 20MB

I still can't send file to email if more than 6MB. Thanks a lot.