Set up Small Business Email in Mozilla Thunderbird
These instructions cover Thunderbird on Windows, macOS and Linux. Small Business Email supports automatic discovery of connection settings when your domain's discovery records are in place. The account should use IMAP and SSL/TLS.
Example domain only:
Wherever you see clientdomain.co.uk, type the domain after the @ in your own email address.
Your Small Business Email package includes a custom mail hostname and webmail URL. In this guide we will use mail.clientdomain.co.uk as a placeholder.
For example, if your email address is joebloggs@clientdomain.co.uk, your server would be mail.clientdomain.co.uk.
Before you begin
Have your full email address and mailbox password available. Use an app password instead if your account requires one for email apps. Your Client Management Portal password may be different. Menu labels vary between Thunderbird versions.
Use automatic discovery
- Open Thunderbird. On the account setup screen, choose to add an existing email address. If you already have accounts, use Account Settings > Account Actions > Add Mail Account, or New Account > Email in versions with the newer account setup screen.
- Enter your name, full email address and mailbox or app password. Choose whether to save the password on this device, then click Continue.
- Allow Thunderbird to discover the settings. Select IMAP if it offers more than one account type.
- Review the result: incoming IMAP must use port 993 and SSL/TLS; outgoing SMTP must use port 465 and SSL/TLS. Both usernames must be your full email address.
- If necessary, choose Manual config or Configure manually and correct the values using the table below.
- Use Re-test if available, then click Done or Finish when the settings verify securely.
Discovery can return a service hostname rather than a hostname beginning with your own domain's mail. prefix. A recognised service hostname can be correct; do not replace it only because it differs from the placeholder. Confirm an unfamiliar hostname with support before entering your password.
Manual settings if needed
| Setting | Incoming | Outgoing |
|---|---|---|
| Protocol | IMAP | SMTP |
| Hostname (placeholder; use your own domain) | mail.clientdomain.co.uk |
mail.clientdomain.co.uk |
| Port | 993 | 465 |
| Connection security | SSL/TLS | SSL/TLS |
| Authentication method | Normal password | Normal password |
| Username | Your full email address | Your full email address |
Normal password describes the authentication method. Your connection is still encrypted because SSL/TLS is enabled. Use your mailbox password, or your app password if required, for both connections.
Check saved settings
Open Account Settings and select Server Settings under your mailbox to check IMAP. For sending, open Outgoing Server (SMTP), select the matching server and click Edit. Make sure this mailbox is assigned to the correct outgoing server.
Test and troubleshoot
Let your folders synchronise, send a message to another address you can access and reply to it. This IMAP account synchronises email; it does not by itself configure calendars or address books.
If discovery fails, recheck the full email address and use the manual settings. If sending fails, check outgoing port 465, authentication and username. Do not accept a certificate exception or turn off encryption to complete setup. Back up any local-only messages before removing an existing account.
Contact us through the Client Management Portal with your Thunderbird version and error message. Never send your password.
