Email not sending

Symptoms

• Messages stay in the outbox, or the mail client reports a send failure.
• The sender receives a bounce message with an authentication or relay error.
• Messages send from some devices but not from others.

Common causes

• The outgoing (SMTP) server, port or security setting is wrong.
• The password for the mailbox is wrong or changed.
• The sending address does not match the mailbox that is signed in.
• Your provider blocks the outgoing port on your network.

Safe initial checks

1. Compare the settings with the values in IMAP and SMTP settings for Business Email, or Email client settings for hosting email.
2. Sign in to webmail with the same mailbox. If webmail sends, the problem is in the mail client.
3. Check the error text in the mail client exactly.

Step-by-step solutions

1. Wrong server or port. Enter the outgoing server name, port and security type exactly as listed in the settings guide.
2. Wrong password. Re-enter the mailbox password. If it is forgotten, reset it. See Forgotten mailbox password.
3. Address mismatch. Set the sender address to the mailbox you signed in with.
4. Port blocked. Try the alternative port listed in the settings guide, or send from another network.

How to confirm the issue is fixed

• A test message to an address you own arrives in the inbox.

When to contact support

Contact support if webmail also fails, the settings are correct, and the error names a server or relay problem.

Information to include in a support ticket

• The mail client name and version, and the exact error text.
• The mailbox address, and the outgoing server and port you used.

Related articles

• Email not receiving
• Emails going to spam
• Email authentication errors
• Spam and troubleshooting

Last reviewed

2026-10-27