No "order complete" email when you mark an order Complete (known problem). Use the Delivered status if you want customers emailed on delivery.
Edited templates keep your text. New placeholders added later (like the delivery slot) don't appear in templates you've changed — add them yourself or Reset to Default.
Missing language version — customers in that language get your default-language email.
Spam folder — the first emails to a new customer can land in spam, especially with your own SMTP and no SPF/DKIM.
Notification Preferences needs the Real-Time Order Notifications module.
No master switch to stop all emails.
Bounces aren't blocked automatically; fix wrong customer emails on their account.
Test orders send real emails to real addresses — use your own email when testing.
