Outgoing email settings
Use the SMTP hostname supplied for your mailbox, with authentication enabled
For current UKC hosted mailboxes, use the exact outgoing server shown in Plesk or your account, your full email address as the username, and SMTP port 587 with STARTTLS. If the app requires implicit TLS, use port 465 with SSL/TLS.
Secure SMTP settings
| Setting | Recommended value | Alternative |
|---|---|---|
| Outgoing server | The exact mail hostname shown for the mailbox | Do not guess if the certificate uses another server name |
| Port | 587 | 465 |
| Encryption | STARTTLS | SSL/TLS |
| Authentication | Required | Required |
| Username | Full email address | Full email address |
| Password | Mailbox password | Mailbox password |
Which SMTP hostname should you use?
Use the server name documented for the mailbox. On current hosted services, the exact Plesk mail hostname is preferable to an assumed name such as mail.example.co.uk because the configured hostname should match the TLS certificate.
Use the UKC service settings
Read the hostname from Plesk or the mailbox setup information. Do not substitute the broadband provider’s server.
Use Microsoft’s settings
A mailbox hosted by Microsoft must use the settings for that Microsoft service, even when UKC manages the domain DNS.
Use Google’s settings
A Workspace mailbox must use Google’s supported SMTP route and account authentication requirements.
Why can I receive email but not send it?
Authentication is disabled
Turn on outgoing-server authentication and use the same full mailbox username and password.
Port or encryption is wrong
Match 587 with STARTTLS, or 465 with SSL/TLS. Do not use port 25 in a normal email app.
Hostname does not match
Replace a guessed mail hostname with the exact supported server name to prevent certificate and connection errors.
The network blocks submission
Compare another trusted network. If webmail works but the app does not, retain the exact error message for diagnosis.
SMTP questions
Should I use my internet provider’s SMTP server?
Normally use the authenticated SMTP service belonging to the mailbox. Old advice to use an ISP relay is unsuitable for many modern domain mailboxes and can complicate identity and delivery checks.
Can I use port 25?
Port 25 is mainly used for mail-server delivery and is often blocked for client submission. Use authenticated port 587 or 465.
Why does SMTP ask for a password?
Authentication proves that the user is authorised to send through the service and reduces unauthorised relay abuse.
What if the certificate name does not match?
Stop and confirm the supported server hostname. Do not disable certificate verification merely to connect.
Need a custom-domain mailbox?
Use a mailbox service with authenticated SMTP and webmail
UKC business email supports secure standard mail protocols and Roundcube webmail.