Common Errors while Connecting through SMTP/IMAP

During the Basic (SMTP + IMAP) connection test SparrowDesk has to:

1. Reach your SMTP server, start TLS (or SSL), and log in.
2. Reach your IMAP server over SSL on port 993 (or STARTTLS on 143) and log in.

If either step fails, SparrowDesk shows

• Internal Error – something broke during the SMTP handshake or authentication.
• Inbox Checking Settings Incorrect – SparrowDesk could not sign in to IMAP or the server refused the connection.

The problem is almost always one of the nine items below.

Quick checks

Confirm the server names exactly match your provider’s docs.

• Common typos: smtpp.gmail.com, imap.gmail.con, missing sub-domain letters.

Use the correct port for the security mode you chose.

• Port 587 + STARTTLS or Auto is the modern default.
• Port 465 + SSL is required on some older or locked-down servers.

Re-enter the username and password—copy-paste removes hidden spaces.

If two-factor authentication is on, create an app password and use it instead of your normal password (Gmail, Outlook, Yahoo, iCloud, Zoho).

Turn on IMAP inside the mailbox settings. Gmail disables it for new accounts; some providers call the switch “Allow IMAP” or “Enable less-secure apps”.

Check that your mailbox isn’t locked or over quota. Some hosts refuse SMTP until you free space or clear security CAPTCHAs.

Temporarily switch Security to “Auto”. SparrowDesk will attempt STARTTLS first, then fallback to SSL, and finally plaintext. If “Auto” works, you know the issue was a security-mode mismatch.

Try a different network or disable the local firewall/VPN for a minute. Corporate firewalls often block ports 465 and 587.

Wait ten minutes and test again. Many providers—especially GoDaddy and Bluehost—rate-limit repeated failed logins and will unlock the account automatically.

Provider-specific pitfalls

Gmail / Google Workspace

• You must enable IMAP in Settings → Forwarding & IMAP.
• For personal Gmail, turn on “2-Step Verification” → “App Passwords” and paste that 16-character password into SparrowDesk.
• If you see a Google “suspicious login prevented” email, click “That was me” and reconnect.

Microsoft 365 / Outlook

• SMTP AUTH may be disabled by your admin. Inside the Exchange Admin Center enable “Authenticated SMTP” for the mailbox.
• On older tenants port 25 might be blocked—always use 587 + STARTTLS.

GoDaddy / cPanel hosts

• Many shared plans block port 465 entirely. Use 587 + STARTTLS.
• Some GoDaddy/Microsoft 365 bundles require you to turn on “SMTP relay” in account security.

Yahoo / iCloud

• These services require app-specific passwords when IMAP or SMTP is used from third-party apps.

Advanced diagnostics

Test SMTP with OpenSSL

openssl s_client -starttls smtp -connect smtp.example.com:587

Test IMAP

openssl s_client -connect imap.example.com:993

Check DNS & firewalls

From the SparrowDesk server’s network (or a machine on the same office LAN) run nc -vz smtp.example.com 587 to confirm the port is reachable.

Make sure no “transparent SMTP proxy” is rewriting or blocking the TLS negotiation.

Still stuck? Gather these details before contacting support

• A full screenshot of the error banner in SparrowDesk (blur passwords).
• The exact SMTP and IMAP servers and ports you typed.
• Whether you use an app password or your main password.
• A note on any firewall, proxy, or VPN that could be filtering traffic.
• The time of your last connection attempt (for log lookup).

Send that bundle to [email protected] or start a chat from the Help Center, and we’ll trace the failure with you.