Quick answer
Configure IMAP with the mailbox's supported TLS settings in Thunderbird. IMAP synchronizes server folders and suits a mailbox used on several devices.
Applies to
For an existing mailbox you are authorized to use in Thunderbird. For Interactive Online hosted mail, copy the exact secure settings from Email Accounts > Connect Devices. Account Hub and older Account Settings setup flows differ by Thunderbird version.
Steps
- Preserve existing local mail before changing account type. Obtain the exact incoming/outgoing hostname, full mailbox username, ports and encryption settings from the service.
- Open the application menu's Add Account/New Account > Email flow, or Account Settings > Account Actions > Add Mail Account in older versions. Enter the mailbox details and review manual configuration if discovery is wrong.
- Select IMAP for incoming mail. Match the service's TLS mode and port; common implicit-TLS ports are 993 for IMAP and 995 for POP. The certificate must match the selected server hostname.
- Configure authenticated SMTP using the service's settings, commonly 465 with SSL/TLS or 587 with STARTTLS. Save and test. Do not follow old video steps that select no encryption or bypass a security warning.
Check the result
Send to and receive from a controlled external address. Confirm the correct SMTP identity and folder synchronization on another authorized device.
Troubleshooting and support
For authentication errors, check the complete mailbox address and saved credentials. For a certificate mismatch, use the supplied secure hostname or contact support; do not disable certificate validation.
If the problem continues, contact support from the account that owns the service. Include the domain, exact error, time and time zone, tool name, and a redacted screenshot. Keep passwords, private keys, cookies and private message content out of the ticket.
Video tutorial
The original video is preserved. Its interface or product version may differ from the written guidance above.
Related help
- Find the correct secure IMAP and SMTP settings for your mailbox
- Choose IMAP or POP for business email
Official references
Written content reviewed November 1, 2026. Menu availability depends on the product version, permissions and service.
