Usually it's a wrong outgoing (SMTP) setting, a changed password, a full mailbox, or the receiving server refusing your mail. Send a test from webmail first: if that works, fix your phone or mail app; if it fails too, the bounce message tells you why.
1. Test in webmail
- Sign in to webmail at
yourdomain.com/webmailwith the full email address and password. - Send a short test message to an address you own at another provider, such as Gmail.
- If it arrives, our server is sending fine and the problem is in your phone or mail app: go to step 2. If it fails or bounces, go to step 3.
2. Fix the app’s outgoing settings
- Outgoing server: the name shown in cPanel’s Connect Devices page, port 465, SSL/TLS. See What are my email server settings?
- Outgoing authentication must be on, with your full email address and the mailbox password.
- Changed the password recently? Enter the new one everywhere. Some apps store the outgoing password separately from the incoming one.
- Fails only on one network, such as office Wi-Fi? Some networks block mail ports. Try mobile data to check, then ask whoever runs that network.
3. Read the bounce message
| If the bounce says | It means | Do this |
|---|---|---|
| Authentication failed, or 535 | Wrong username or password | Use the full email address; set a new password |
| Quota exceeded, or mailbox full (your address) | Your mailbox or hosting space is full | Free space: see My mailbox is full |
| User unknown, or address not found | The recipient’s address is wrong | Check the spelling |
| SPF, DKIM, DMARC, or 550 5.7.x | The receiving server doesn’t trust your domain’s mail | Repair your records: see SPF, DKIM and DMARC |
| Blocked, listed, or blacklist | The sending server or address has been flagged | Open a ticket with the full bounce |
4. If nobody on your domain can send
- Check the domain hasn’t expired: see What happens when my domain expires?
- A hacked mailbox sending spam can get sending paused for the whole account, which protects everyone else on the server. Change passwords and tell us: see My email account has been hacked.
- Sending one message to hundreds of people from a normal mailbox looks like spam to receiving servers. Use a mailing service for newsletters.
When you contact us, paste the whole bounce message, including the technical lines at the bottom. It usually names the exact cause.
Still stuck? Open a support ticket with your email address and the bounce message, or message us on WhatsApp, Monday to Friday, 08:00–17:00 CAT.
Updated 6 November 2026. Something here out of date? Tell us.