Obtain the exact service settings
Use the real mailbox provider's incoming and submission settings, and test both directions before relying on the new client.
Configure only a mailbox your service actually provides. Obtain its incoming protocol, server, port and TLS mode, plus the authenticated submission server and username, from the mail operator. Generic DirectAdmin or Thunderbird settings cannot establish your account’s entitlement or endpoints.
Install a maintained mail client from its trusted publisher. Keep the mailbox password in a password manager, and confirm you control the mailbox and any recovery method before adding devices.
Choose IMAP or POP deliberately
IMAP normally keeps messages and folders synchronised with the server across devices; POP normally downloads messages and has different retention behaviour. Choose the protocol the provider supports and that fits your backup and multi-device needs. In Thunderbird’s manual setup, enter the actual incoming hostname, full username if required, documented port and TLS setting. Validate the certificate name against the server you were given. A certificate warning needs an operator check; do not accept an unrelated certificate.
Let the client discover settings only as a proposal, then compare them with the provider’s values. Do not assume that the website’s domain or MX target is also an IMAP endpoint. Configure only accounts for which you have authorisation.
Configure authenticated submission separately
Set the outgoing SMTP server to the provider’s documented submission endpoint and supported encrypted mode. Enable the authentication method it specifies. An incoming connection succeeding does not prove outgoing submission is configured. Where the client offers several saved outgoing servers, bind the new identity to the correct one, and ensure the visible From address is authorised by the account.
If login fails, check the full username, server, password and any application-specific credential requirement through the provider. If a connection or TLS check fails, verify the network and certificate before trying another setting. Do not choose plain, unauthenticated SMTP or turn off TLS validation as a workaround.
Test sending and receiving separately
Send a non-sensitive message to an external mailbox you control and verify arrival and the From address. Reply to the configured mailbox, confirm server-side arrival through webmail if provided, then confirm client synchronisation and folder placement. A copy in Sent is not proof of remote delivery. Keep the provider’s webmail or other recovery route until both tests work.
A successful test has two observations: the external recipient receives the new outbound message, and the reply appears on the server and then in the client.
If only outgoing fails, use the related sending guide; if only incoming fails, use the receiving guide. Revert a mistaken account configuration or remove the new device profile without deleting server-side messages. Record the exact error and time for support, never the password.
Common questions
Can I copy settings from another provider? No. Server names and security modes belong to the actual mailbox service.
Is SMTP the same as IMAP? No. SMTP submits outgoing mail; IMAP retrieves and synchronises incoming mail.
Should I ignore a certificate warning? No. Verify the endpoint and certificate with the provider.
Can a successful outgoing test stand in for an incoming test? No. Submission and retrieval use different servers and settings.
Sources and technical references
Related guides
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