Email Client Settings

Overview

Email client settings control how Omnium sends email: order confirmations, notifications, comment emails and other transactional mail. You choose one email service for the tenant and enter its connection details. You also set the default sender address, how replies to comment emails come back, and some content options.

The configuration is located under:

Configuration → Settings → Communication → Email client

Changing these settings requires an administrator.

Email services

The Email service field selects the service Omnium sends email through. When it is empty, Omnium sends no email.

The email service and its connection details apply to the whole tenant. Emails for every market and market group go through the same service. See Email settings on markets and market groups.

Compare the email services

All three services send notifications, comment emails and other single emails with attachments. They differ in these ways:

The reply-to address matters for comment emails: with SMTP, a customer's reply goes to the sender address and does not come back as a comment.

Email service settings

The fields on the Email service card depend on the email service you select.

SendGrid

• When SendGrid API key is empty, Omnium sends no email, and the event log shows no error.
• Omnium ignores a server address that does not contain sendgrid and uses https://api.sendgrid.com. Clear the field when you switch from SMTP to SendGrid.
• Omnium does not send an email without a subject through SendGrid.

SMTP

Omnium sends no email through SMTP until both the server address and the port are set. It always connects with TLS through STARTTLS, so a server that only offers implicit TLS on port 465 does not work.

When the mail server does not accept an email, Omnium does not try again. It logs an Error sending email event with the server's error. SMTP sends no reply-to address and no newsletters, see Compare the email services.

Microsoft 365 (Graph API)

The Send test email button sends a test email to you with the values in the form, also before you save them. See Test the setup.

Send email through Microsoft 365

With the Microsoft 365 (Graph API) email service, Omnium sends each email with the Microsoft Graph sendMail API. Omnium signs in as your own app registration in Microsoft Entra ID with the OAuth 2.0 client credentials flow (app-only access), so no username or password is used. The email leaves from Exchange Online, as it does with SMTP through Microsoft 365, so your SPF and DKIM setup does not change.

Your Microsoft 365 administrator sets up the app once. Then you enter its details in Omnium.

Register the app in Microsoft Entra ID

1. In the Microsoft Entra admin center, register a new application for your own tenant only (single tenant).
2. Note the Directory (tenant) ID and the Application (client) ID.
3. Create a client secret. Note its value and when it expires. Microsoft Entra ID allows a lifetime of at most 24 months.

Give the app permission to send

The app needs the Microsoft Graph application permission Mail.Send. You can give it in two ways:

• Limited to the sender mailbox (recommended). Use RBAC for Applications in Exchange Online. The app can then only send as the mailboxes in the scope you set.
• For all mailboxes. Grant the Mail.Send application permission in Microsoft Entra ID with admin consent. The app can then send as any mailbox in your tenant.

To limit the permission to one mailbox, connect to Exchange Online PowerShell and run these commands. The object ID is the one on the app's Enterprise applications page, not on the App registrations page.

New-ServicePrincipal -AppId <application-client-id> -ObjectId <enterprise-app-object-id> -DisplayName "Omnium mail"
New-ManagementScope -Name "Omnium sender" -RecipientRestrictionFilter "PrimarySmtpAddress -eq 'webshop@contoso.com'"
New-ManagementRoleAssignment -App <enterprise-app-object-id> -Role "Application Mail.Send" -CustomResourceScope "Omnium sender"

Check the result with Test-ServicePrincipalAuthorization -Identity <enterprise-app-object-id> -Resource webshop@contoso.com. It shows InScope as True for the sender mailbox.

For details, see Microsoft's documentation on RBAC for Applications in Exchange Online.

Configure Omnium

1. Go to Configuration → Settings → Communication → Email client.
2. Set Email service to Microsoft 365 (Graph API).
3. Enter the Directory (tenant) ID, the Application (client) ID, the Client secret and the Sender mailbox.
4. Turn on Save a copy in Sent Items if you want a copy of every email in the sender mailbox.
5. Press Send test email, and save when the test email arrives.

Test the setup

Send test email sends an email to the email address of your Omnium user, through Microsoft Graph, with the values in the form. When the test fails, the message tells you why, for example:

How Omnium sends through Microsoft 365

• Sender. Every email is sent from the sender mailbox. When an email has another sender address, for example a store's address in a notification template, and no reply-to address of its own, that sender address becomes the reply-to address, so replies still reach it.
• Size. Microsoft Graph accepts at most 4 MB in one request, and attachments grow by about a third when they are sent. An email can carry about 3 MB of attachments. Omnium does not send an email that is larger, and logs an error event that gives its size.
• Throttling. Exchange Online allows each mailbox to send 30 messages a minute and to 10,000 recipients a day. When Microsoft throttles the mailbox, Omnium waits as long as Microsoft asks and tries again, with at most 3 tries and 60 seconds of waiting in all. When Microsoft asks for a longer wait, Omnium does not send the email and logs an error event. See Microsoft's Exchange Online limits.
• Timeouts. When Microsoft Graph does not answer in time, Omnium does not send the email again, because Microsoft may already have sent it.
• Errors. An email that is not sent gives an error event, Error sending email, in the event log. The event says what went wrong. When Microsoft answered, it also includes Microsoft's request ID, which Microsoft support asks for.
• Newsletters. Exchange Online is not made for bulk email, so newsletters cannot be sent through Microsoft 365. Use SendGrid for newsletters.

Sender and replies

Email content

Email settings on markets and market groups

A market or a market group has no email service of its own. It can have its own values for some email fields, in the EmailClientSettings of the market or market group. On a market, only the sender address has a field, Default e-mail address on the market's E-mail card. The other fields are set in the market's or market group's settings.

The other fields, such as the email service, its connection details, Language of the reply line and Show product ID instead of SKU, are read only from the tenant. A value on a market or market group has no effect.

Related documentation

• SendGrid
• Inbound email for cases
• Markets configuration
• SMS Client Settings