When reauthorizing your support email account in BoldDesk, and facing this error indicating:

It typically denotes that your email client (BoldDesk) is unable to connect to your email provider’s SMTP server, which is required to send emails.

Troubleshooting SMTP Connection Error

1. Verify SMTP server settings (custom mail server only)

If the support email is configured using a custom mail server, confirm that the SMTP configuration in BoldDesk matches the email provider’s required settings.

Validate all of the following:

• SMTP server hostname
• Port
• Encryption (SSL/TLS)
• Authentication requirements (username/password, app password, etc., based on provider policy)

Use the provider’s official documentation to confirm the correct values.

2. Enable SMTP access for the mailbox (Microsoft 365)

If the support mailbox is in Microsoft 365, ensure Authenticated SMTP is enabled for that mailbox.

• This is a mailbox/org policy controlled by the Microsoft 365 administrator.
• If authenticated SMTP is disabled, SMTP connectivity from third‑party clients can fail.

Learn more on Troubleshooting Email Errors: Enabling IMAP and SMTP Access in Office 365.

3. Check network and firewall restrictions

Outbound SMTP connections can be blocked by:

• Corporate firewall policies
• Network security appliances
• ISP restrictions
• Endpoint security rules on the server/workstation

Have the network administrator confirm outbound access is permitted to the email provider’s SMTP endpoint on the required port(s).

4. Confirm the correct mailbox is used during Reauthentication

During Reauthenticate, the provider login page may auto-select a browser-signed-in account (for example, a personal Microsoft account). If the signed-in account does not match the BoldDesk-configured support mailbox, reauthorization can fail and surface as a generic SMTP connection error.

Ensure authentication uses the correct support mailbox

1. In BoldDesk, go to Admin → Emails.
2. Open the affected support email.
3. Click Reauthenticate.
4. On the provider sign-in page, sign in using the same email address as the configured support mailbox.
   • If another account is auto-selected, switch accounts and select the correct mailbox.

If the browser keeps selecting the wrong account

Use one of the following:

• Reauthenticate using a private/incognito window (prevents reuse of cached sessions).
• Sign in to the browser with the support mailbox account (separately), then reauthenticate again.
• Try a different browser. If it works elsewhere, the issue is typically cached login/session state in the original browser.

If the issue persists after following the above steps, reach out to BoldDesk support for further assistance.

SMTP authentication error

Issue
While configuring SMTP in BoldDesk, you may see:
“An error occurred when authenticating to your SMTP server. Verify your SMTP settings and try again.”
This can happen even after updating the password.

Cause
Some SMTP providers treat the email/username as case-sensitive. If the email address entered in BoldDesk doesn’t match the exact letter casing of the mailbox (as registered/recognized by the provider), authentication can fail even with the correct password.

Resolution

• Re-enter the Username/Email in the SMTP settings using the exact casing required by your email provider.
• Save the changes and try authentication again.

Frequently Asked Questions

1. What does the message “Unable to establish an SMTP connection…” mean during reauthentication?
   This message means BoldDesk cannot complete an outbound connection to the SMTP service needed to send emails (ticket replies/notifications) during support email setup or reauthentication. It’s most commonly caused by incorrect SMTP configuration, SMTP being disabled for the mailbox (Microsoft 365), network/firewall blocks, or reauth being performed with the wrong mailbox account.

2. When should I verify SMTP server settings in BoldDesk?
   Verify SMTP server settings only when your support email is configured to use a custom SMTP server for outbound email. Confirm these values match your provider’s required settings: SMTP host, port, encryption (SSL/TLS), and the correct authentication method/credentials.

3. What Microsoft 365 setting can cause this SMTP connection message during reauthentication?
   If your support mailbox is in Microsoft 365 and Authenticated SMTP is disabled (mailbox-level or org-level policy), SMTP connectivity from third‑party apps can fail and surface as this SMTP connection message. Enable Authenticated SMTP for the mailbox in Microsoft 365 admin settings.

4. Can network or firewall restrictions trigger the same SMTP connection message?
   Yes. Corporate firewalls, network security appliances, ISP restrictions, or endpoint security policies can block outbound SMTP connections to your provider’s SMTP endpoint/port, causing this SMTP connection message.

5. Why can the same SMTP connection message appear even when SMTP settings look correct?
   Because the message can also occur when the wrong mailbox is used during Reauthenticate. The provider sign-in page may auto-select an account already signed in to your browser. If that account does not match the BoldDesk-configured support mailbox, reauthentication can fail and still show this SMTP connection message.