Help Scout

Help Scout can send an inbox's replies through a Microsoft 365 mailbox with a Microsoft sign-in, and Footer365 signs mail that passes through your Microsoft 365. Choose how your CRM or app sends its mail explains the two ways to send, and this guide follows the first.

At a glance

• Can be signed: replies from an inbox whose custom email address is "a full Microsoft 365 Outlook user mailbox" and that uses Help Scout's Microsoft 365 OAuth sending. Help Scout says: "Microsoft will save a copy of that sent email in your Outlook Sent Items for that account."
• Cannot be signed: replies from an inbox that does not use this connection. The article does not say which servers Help Scout sends from in that case.
• How it connects: OAuth, in a two-person process. Help Scout says: "This is a two-person process: you'll start the connection, your Microsoft 365 Administrator will approve it."
• Status: from Help Scout's documentation as read on 23 October 2026, not tested by Footer365. The article is updated 9 September 2026.

Before you start

• Footer365 mail flow is set up. With the Outlook add-in only, no mail Help Scout sends is signed. Using the Outlook add-in only
• The mailbox has a Footer365 signature rule that covers it, so a support address needs a rule of its own.
• Someone who can approve apps in your Microsoft Entra admin centre is ready for step 1.

Step 1: Approve the app in Microsoft 365

Help Scout's article does not list the permissions. When the person starts the connection, Microsoft asks for approval, and an administrator then approves it: Help Scout says to use Enterprise Apps > Admin consent requests in the Entra admin center, review the permissions and consent, and accept the permissions. Approve an app's access in Microsoft 365

Step 2: Choose the mailbox

• A full Microsoft 365 user mailbox is the only kind the article describes. The mail is signed with the signature your rules give that mailbox.
• A shared mailbox: Help Scout's article does not mention shared mailboxes or aliases, and says only that the custom address must be a full Microsoft 365 Outlook user mailbox. Do not assume a shared mailbox works.

Step 3: Connect it in Help Scout

Following Help Scout's steps, the person starts the connection:

1. Select Settings (the gear icon) > Inboxes > the inbox > Outgoing Email.
2. Follow Help Scout's steps there to start the Microsoft 365 connection.
3. Ask your Microsoft 365 administrator to approve it, as in step 1.

Help Scout's own steps: Use Microsoft 365 OAuth to send from Help Scout.

Step 4: Check one message

1. Reply to a test conversation from an address outside your organisation that you can read.
2. Open the headers of the copy you receive.
3. Return-Path should be the mailbox's address, and X-Footer365-Relay-Id should be there.
4. Look in the mailbox's Sent Items, where Help Scout says Microsoft keeps a copy.

What other results mean: Mail from our CRM is not signed.

Where the signature goes

Help Scout's article does not describe a signature setting for this connection. If you see two signatures, remove Help Scout's. To place Footer365's signature in a template, use a marker, and check one message, because the article does not say what Help Scout does with text in double braces. Place the signature with a marker

What is not signed

Help Scout's article does not describe email that Help Scout sends from its own servers. A message without X-Footer365-Relay-Id did not pass through your Microsoft 365.

What stops working

The article does not mention Exchange Web Services, Basic authentication or any date. Help Scout describes the connection as OAuth, which Microsoft's announced change for Basic authentication does not affect.

Limits

Help Scout's article states no sending limit. Microsoft's limits for a mailbox apply: 10,000 recipients a day and 30 messages a minute. Microsoft: Exchange Online limits

Last resort: a connector to Exchange Online

Help Scout's article describes no connector from Help Scout into Exchange Online, and Help Scout runs on its own servers. Microsoft says SMTP relay cannot be used for a service hosted by someone else, and asks such a service for a certificate of your own. So there is no connector route for Help Scout mail. Last resort: a connector to Exchange Online

If it does not work

1. The connection waits. Your administrator has not approved it yet. Check Admin consent requests.
2. The address is not a full user mailbox. Help Scout says OAuth needs one.
3. The message has no X-Footer365-Relay-Id. It did not pass through Microsoft 365.
4. It passed through Footer365 but is unsigned. The wrong signature is used for a shared mailbox or delegate
5. Still not clear. Mail from our CRM is not signed

Sources

Read on 23 October 2026:

• Help Scout: Use Microsoft 365 OAuth to send from Help Scout, updated 9 September 2026.