Mail troubleshooting

Common mail issues and how to diagnose them.

Can't send mail

Symptoms: client says "authentication failed" or "could not connect".

• Username should be the full email address, not just the part before @
• Use port 587 with STARTTLS, or port 465 with SSL. Not port 25 (which we block for outbound)
• Some ISPs (BT, Virgin, etc.) block outbound 25 — not the problem here, but related

Outgoing mail goes to spam at Gmail/Microsoft

First-time mail from a new domain often gets filtered. Things that help:

• Make sure SPF, DKIM, DMARC records exist (check on the Domain DNS tab)
• Send some legit mail to humans over a few days — builds reputation
• Don't send to large mailing lists from a new domain right away
• Check the Spamhaus reputation lookup for your sending IP

Incoming mail not arriving

Check, in order:

1. MX records on your domain — should point at our mail server
2. Is the mailbox in quarantine? Check the MxGuard quarantine tab
3. Is the sender's domain in your block list?
4. Ask the sender if they got a bounce message

Quarantined mail

MxGuard holds mail that scored above the spam threshold. Check Mail → Quarantine. Release legit mail and add the sender to your allow rules.