If you can receive mail but cannot send email, the problem is almost always the outgoing (SMTP) settings in your mail app. This guide walks through the usual causes of SMTP authentication errors, "relay not permitted" messages and mail stuck in the Outbox, in the order to check them.
Step 1: Check the outgoing server settings
Open your mail app's account settings and find the outgoing server (SMTP) section. It should match this:
| Setting | Correct value |
|---|---|
| Outgoing server | mail.example.com (or secure.instantaccess.net) |
| Port and security | 465 with SSL/TLS, or 587 with STARTTLS |
| Authentication | On / "My outgoing server requires authentication" ticked |
| Username | Your full email address |
| Password | Your email account password |
You can confirm the exact server name in cPanel under Email > Email Accounts > Connect Devices. See Email Server Settings and Ports (IMAP, POP3 and SMTP) for more detail.
Step 2: Make sure SMTP authentication is turned on
The Instant Access Internet Services server only sends mail for people who log in. If authentication is off, you'll see errors like 550 relay not permitted, authentication required or sender verify failed. Where to find the setting:
- Outlook: in the account's server settings, open the outgoing server section and make sure it requires sign-in, using the same credentials as incoming mail.
- Thunderbird: Account Settings > Outgoing Server (SMTP) > Edit, authentication method Normal password.
- iPhone/iPad: Settings > Apps > Mail > Mail Accounts > your account, then tap the account details and open SMTP under Outgoing Mail Server. Tap the primary server and make sure username and password are filled in and Use SSL is on.
- Android / Gmail app: in the account's outgoing settings, make sure "Require sign-in" is on.
Menu names vary between app versions; look for "outgoing server", "SMTP" or "authentication".
Step 3: Check the username and password
The username must be the whole address (you@example.com), not just "you". Test the password by logging in to webmail (see How to Log In to Webmail (Roundcube)). If webmail rejects it, reset it in cPanel (How to Change an Email Account Password in cPanel) and then update it on every device -- including the outgoing server password, which some apps store separately.
Step 4: Try the other port
Some internet providers, hotels and office networks block certain mail ports. If port 465 times out, switch to 587 with STARTTLS, or the other way round. If it works on your phone's mobile data but not on Wi-Fi, the network is blocking it.
Step 5: Test from webmail
Send a message from Roundcube webmail. If that works, the mailbox and server are fine and the problem is in the app's settings. If webmail also fails to send, open a ticket.
Common error messages
"535 Incorrect authentication data"
Wrong username or password. Use the full email address and re-enter the password.
"550 relay not permitted" or "Please turn on SMTP authentication"
Authentication is switched off, or the app is sending through a different server than the one you log in to. Turn on authentication and point the outgoing server at mail.example.com.
"The server does not support secure connections" or SSL errors
The port and security type don't match. 465 needs SSL/TLS; 587 needs STARTTLS. If you get certificate warnings, use secure.instantaccess.net as the server name.
Messages sit in the Outbox with no error
Usually a blocked port or a very large attachment. Try the other port and send a small test message. Large files are better shared with a download link.
Mail sends, but the other person never gets it
That's a delivery problem rather than a sending problem. Check for a bounce message (How to Read a Bounce Message (Common Email Errors Explained)), look the message up in cPanel's Track Delivery tool (How to Find a Missing Email with Track Delivery), and read Why Your Emails Go to Spam (and How to Fix It) if it's landing in spam.
Everything stopped at once -- email, website and cPanel
A device repeatedly trying an old password can trigger our firewall, which temporarily blocks your IP address. Update or remove the old device, look up your IP at whatismyipaddress.com, and send it to us in a ticket so we can unblock it.
Related guides
- Email Server Settings and Ports (IMAP, POP3 and SMTP)
- How to Find Your Email Settings with Connect Devices
- How to Find a Missing Email with Track Delivery
- How to Read a Bounce Message (Common Email Errors Explained)
- Why Your Emails Go to Spam (and How to Fix It)
Still stuck? Open a support ticket and the Instant Access Internet Services team will help.
