Why can’t I send emails?

There are a few very common reasons why you may not be able to send emails using 20i email hosting.

Are your email settings correct?

Make sure the email account username and password that you enter in your email client are correct. The details you’ll need to be using are found below:

Account type: IMAP

  • Incoming mail server: imap.stackmail.com
  • Outgoing mail server: smtp.stackmail.com
  • Incoming server port (IMAP): 993
  • Use the following type of encrypted connection: SSL
  • Outgoing server port (SMTP): 465 (or 587)
  • Use the following type of encrypted connection: TLS

For further information, please see: How do I setup my 20i mailbox in Outlook?

Are email sending limits being hit?

Our mail platform has several limits in place to protect the reputation of the mail platform and prevent large quantities of spam emails from being sent. Currently, our mail limits are as follows:

Web servers: 500 emails a day.
Mailboxes: 8000 emails a day.
Message size/attachments: our webmail system accepts attachments up to 32 MB in size, and the maximum message size in our network is 50 MB.

If any of these limits are breached, then it won’t be possible to send mail from that hosting package or mailbox. In the case of the message size/attachment limit, you’ll simply need to look at reducing the size of the email or the attachment being sent.

Where do the MX records point?

You can easily ensure 20i serves the emails by using the tool here: https://mxtoolbox.com

If we host the emails then you’ll see mx.stackmail.com returned. If anything else is returned you may wish to contact the provider to determine the cause of the issue.

Is the mailbox disabled for suspicious activity?

If you’re receiving the following error when trying to send the mailbox may have been disabled for sending suspicious emails.

SMTP: Error (550): Failed to add recipient “[email protected]” (Sending mail from this address has been disabled due to suspicious activity).
If you’ve received this error, please get in touch with our Support Team, they’ll be able to get this resolved for you.