Email may fail to send because of an application setting, sign-in problem, mailbox restriction, oversized attachment, or a recipient-server rejection. The first step is to identify where the message stops.
Try a simple test
- Write a new email with a short subject and no attachments.
- Send it to another email address you control.
- Check your Outbox and Sent Items folders. A message stuck in Outbox often points to an app or connection problem.
- If you receive an automated delivery-failure notice, save the notice and any error code.
Check the mailbox in webmail
- Sign in using your email provider’s approved webmail address. For agency-provided email this may be
https://webmail.yourdomain.com. - Send the same short test message from webmail.
- If webmail sends successfully but your desktop or phone app does not, check the app sign-in and account settings.
- If webmail also fails, report the issue to support with the error details.
Common causes
- Incorrect credentials: The email app may be using an outdated password or account token.
- Wrong mail settings: Manually configured applications must use the server details supplied for that mailbox.
- Large attachments: Some messages exceed your email service’s attachment-size limit.
- Recipient rejection: A recipient’s mail server may reject a message for policy or address-related reasons.
- Account restrictions: A provider may limit sending after suspicious activity or a service issue.
What not to do
Do not change your domain’s MX, SPF, DKIM, or other DNS records just because one message failed. Those changes can interrupt email for everyone using the domain. Ask support to investigate first.
Still need help?
Submit a support ticket with the sending address, recipient address, approximate send time and time zone, device/app, and the full non-sensitive error or bounce message. Do not send passwords or authentication codes.