Using Office 365 Outlook Connector in Logic Apps Standard || Connection Issue in Workflow Designer

Introduction

When working with Azure Logic Apps Standard, it’s common to manage API connections centrally using ARM/Bicep and then reference them from workflows using connections.json.

Recently, while configuring the Office 365 Outlook (V2) connector with Managed Identity authentication, I ran into an interesting designer issue that is not obvious at first glance.

The connector worked perfectly at runtime — but the Logic App designer failed to automatically bind the existing connection, resulting in a broken trigger definition until manually fixed.

This blog walks through:

• How to correctly create and reference an Office 365 Outlook API connection
• How to configure Managed Identity authentication in Logic Apps Standard
• The designer bug/limitation
• The exact fix and why it works

Key components involved:

• Logic Apps Standard (single-tenant)
• Office 365 Outlook (V2) managed API connection
• System-assigned or User-assigned Managed Identity
• connections.json
• Workflow designer (portal)

Step 1 – Creating the Office 365 Outlook API Connection

The Office 365 connector is deployed as a Microsoft.Web/connections resource.

ARM Template (API Connection)

{
  "type": "MICROSOFT.WEB/CONNECTIONS",
  "apiVersion": "2016-06-01",
  "name": "[parameters('office365ConnectionName')]",
  "location": "[parameters('resourceLocation')]",
  "kind": "V2",
  "properties": {
    "api": {
      "id": "[concat(subscription().id, '/providers/Microsoft.Web/locations/', parameters('resourceLocation'), '/managedApis/office365')]"
    },
    "displayName": "Shared Office 365 V2",
    "parameterValues": {}
  }
}

✔️ After deployment, the connection is authorized interactively
✔️ An Access Policy is added so the Logic App’s Managed Identity can use it

Step 2 – connections.json Configuration (Logic Apps Standard)

In Logic Apps Standard, workflows do not directly embed secrets. Instead, they reference connections via logical names defined in connections.json.

{
  "managedApiConnections": {
    "office365": {
      "api": {
        "id": "@appsetting('Office365_ApiId')"
      },
      "connection": {
        "id": "@appsetting('Office365_ConnectionId')"
      },
      "connectionRuntimeUrl": "@appsetting('Office365_ConnectionRuntimeUrl')",
      "authentication": {
        "type": "ManagedServiceIdentity"
      }
    }
  }
}

🔑 Important:
office365 here is the connection reference name — this becomes critical later.

Step 3 – The Designer Problem

When creating the trigger “When a new email arrives in a shared mailbox (V2)”, the Logic App designer should automatically pick up the existing Office 365 connection.

Instead, the workflow JSON looked like this:

"host": {
  "connection": {
    "referenceName": null
  }
}

What this causes

• The trigger appears unbound in the designer
• You’re prompted to create or select a connection
• The workflow will not run
• No clear error message explains why

This happens even though:

• The connection exists
• It’s authorized
• Managed Identity access policy is configured
• connections.json is correct

Step 4 – The Fix (Manual but Effective)

The fix is simple once you know what’s missing.

Update the workflow JSON and explicitly set the connection reference name:

"host": {
  "connection": {
    "referenceName": "office365"
  }
}

Once saved:

✅ Designer immediately recognizes the connection
✅ Trigger configuration UI loads correctly
✅ Workflow runs without issues

Designer Limitation

This appears to be a limitation with the Logic Apps Standard designer, observed in both the VS Code Logic Apps Standard extension and the Azure Portal designer.

Even though the Office 365 connection is correctly configured, authorized, and works at runtime, the designer does not always auto-bind the existing API connection. As a result, the workflow is generated with a null referenceName, which must be manually corrected for the designer to recognize the connection.

Once the referenceName is explicitly set, the designer immediately resolves the connection and the workflow functions as expected.