New feature, Security

The size limitation of email with an attachment has changed to 15 MB

Aleksandra Duło, 21 April 2022


From May 1st this year, the maximum size of an email with an attachment on our platform will be limited to 15MB. Senders who exceed the allowable limit should optimize their message design and/or review the attachment file size.

Why is there a maximum Email size limit introduced?

Some inbox providers also enforce maximum email size limits. There are several hundred billion messages sent worldwide every day so limits are necessary. Each recipient’s email provider has it; without a maximum message size, email servers with high volume sends of large messages will encounter difficulties and may even cease to work properly. Large messages with attachments are often sent by spammers, which makes them even more unwelcome by mailbox providers.

  • Gmail – 25MB (per email sent or received)
  • i Hotmail – 10MB (per file attachment)
  • Yahoo Mail – 25Mb (per email) or unlimited (only for files attached via DropBox)
  • WP Mail,, – 100MB
  • Onet Mail – 50MB

What happens when you exceed the Email size limit?

Emails exceeding the 15MB limit will be rejected and will receive the following error message:

  • For SMTP mailings: “552: Message size exceeds outgoing Email size limit. The Email was not sent; reduce the message size and try again.”
  • For mailings via API: “code: 413, error message: Email size exceeds outgoing message size limit. The Email was not sent; reduce the message size and try again.”

To deliver messages correctly, optimize the email content design and the attachments themselves, which instead of attaching them to your email, are worth linking to them in the body of the message. If you need support or would like to increase your message limit, please contact us.

Most popular

Latest blog posts