Invoices, password resets and ticket notifications all depend on outbound mail, so this is worth fixing properly rather than working around.

1. Check the SMTP settings

Go to Settings → Email and confirm the host, port, username, password and encryption. Send a test message and read the exact error — it usually names the problem directly.

2. Try a different port

• 587 with STARTTLS — try this first.
• 465 with implicit TLS.
• 25 — blocked outbound by most providers; avoid it.

The encryption setting must match the port. Port 587 with implicit TLS selected will fail, as will 465 with STARTTLS.

3. Check the firewall

Test whether the server can reach your mail host at all:

telnet smtp.yourprovider.com 587

If it hangs, outbound SMTP is blocked and your host will need to open it.

4. Check authentication

Many providers require an app-specific password rather than your normal account password, particularly where two-factor authentication is enabled.

Mail sends but lands in spam

This is a DNS problem, not a WHMAZ problem:

• SPF — publish a record authorising your sending host.
• DKIM — enable signing at your mail provider and publish the key.
• DMARC — add a policy record once SPF and DKIM are in place.
• Send from your own domain. A from-address at a free mail provider will fail authentication checks.

Use a dedicated transactional mail provider if deliverability matters to you. Sending invoices from a shared server IP with no reputation is an uphill battle.