What this does
By default, Invocourier emails invoices from invocourier.com, with your company name as the sender and your contact address as Reply-To. That works, but the buyer's mail program still shows an address that is not yours. Connect your own mail server and invoice and credit-note emails go out from your address, authenticated by your own provider, exactly like mail you send yourself.
Archive copies, the uninstall export link and service notices keep coming from invocourier.com, so they still reach you when your server is the thing that broke.
This applies to email delivery only (Germany, and PDF invoices to consumers). Belgian B2B invoices travel over Peppol and are not affected.
Setting it up
Open the app's Settings, section Send invoice emails from your own mail server.
- Email provider: pick yours and the server name, port and encryption are filled in. Pick Other to type them yourself.
- Username and password: the credentials of the mailbox that will send. Some providers need an app password or a setting on their side, see the table below.
- Send from: the address buyers will see. It must be one your mail server is allowed to send from, usually the mailbox you log in with.
- If my mail server fails, send from invocourier.com instead: on by default, see "When your server fails".
Click Save mail server, then Send test email. The app connects to your server, logs in and sends a real message through it to your contact address. Only after that test passes is your server used. Until then, and after any change to the connection details, invoices keep going out from invocourier.com, so nothing is ever stuck on a typo.
Your password is stored encrypted and is never shown again. When you edit the other fields later, leave the password blank to keep it.
Provider notes
| Provider | What to know |
|---|---|
| Google Workspace, Gmail | Enable two-step verification on the account, then create an app password (Google account → Security → App passwords) and use it instead of your normal password. Gmail rewrites the From address to the logged-in mailbox unless the address is set up as a "Send mail as" alias. |
| Microsoft 365, Outlook | Your Microsoft 365 administrator must enable Authenticated SMTP for the mailbox (Microsoft 365 admin center → Users → Mail → Manage email apps). Microsoft is phasing out password-based SMTP; if it stops working, ask your administrator or use a transactional email service. |
| IONOS, STRATO, Hetzner, mailbox.org, OVH, Gandi, Infomaniak, Combell, TransIP, one.com | Standard mailbox credentials work. Use the mailbox address as username unless your provider says otherwise. |
| GMX, WEB.DE | Enable "POP3/IMAP access" in the mailbox settings and, with two-factor authentication on, create an app password. |
| Brevo, Mailjet, Postmark, Mailgun, Amazon SES | Create SMTP credentials in the service's dashboard and verify your sending domain there first. The From address must be on a verified domain. |
| SendGrid | The username is the literal word apikey; the password is an API key with "Mail Send" permission. |
| Scaleway Transactional Email | The username is your project ID; the password is the secret key of an API key with Transactional Email permissions. |
Only encrypted connections are accepted: STARTTLS (usually port 587) or TLS/SSL (usually port 465). Shopify itself does not offer an outgoing mail server.
When your server fails
A changed password, a provider blocking the login or a server outage makes a send fail. The app retries such failures automatically. After three failures in a row your server is marked as failing, you get an email from invocourier.com, and Home shows a notice.
With "send from invocourier.com instead" on (the default), the affected documents and everything after them are delivered from invocourier.com in the meantime, so your customers still receive their invoices. Your server is tried again every hour and taken back into use automatically as soon as it works. With the option off, documents wait and are retried on the usual schedule; nothing is delivered until your server works again.
To fix it: correct the credentials in Settings and click Send test email. A passing test puts your server back in use immediately. Each invoice's delivery details say which server carried it.
Deliverability
Mail sent this way carries your domain's SPF and DKIM as configured by your provider, which is what makes it land in the inbox. If you use a transactional email service, verify your domain there before sending. Invocourier does not change your DNS.
Removing it
Remove mail server deletes the stored credentials at once; invoices go out from invocourier.com again. Credentials are also deleted when you uninstall the app.