---
title: "❓ Outlook Add-In (new): SecuMails are sent unencrypted"
url: "https://support.ftapi.com/en/article/outlook-add-in-neu-secumails-werden-nicht-verschluesselt-versendet"
language: "en"
last_updated: "2026-06-22T07:11:12.918Z"
---

# ❓ Outlook Add-In (new): SecuMails are sent unencrypted

If the FTAPI Outlook Add-In triggers a delivery in the new Outlook, but the email arrives unencrypted and an HTTP 400 error appears in the Dev Log, a Microsoft privacy setting is usually disabled.

## Symptom

The user is logged into the FTAPI Outlook Add-In. When sending a SecuMail, an `HTTP 400 Bad Request` becomes visible in the **Network tab of the Outlook Developer Tools**. The delivery is sent unencrypted, even though the Add-In is open.

> **The Outlook Developer Tools can be opened via the command line using** `**olk.exe --devtools**`**. The window will appear automatically the next time Outlook is started.**

## Cause

The FTAPI Outlook Add-In in the new Outlook is based on Microsoft's web add-in architecture and uses cloud-based services to exchange data between the compose window and the add-in. If the **Turn on optional connected experiences** setting is disabled in the privacy settings, Microsoft blocks this communication. The add-in cannot correctly intercept the sending process, and the delivery is sent unencrypted.

## Solution

The affected person must enable the following setting in Outlook:

`Settings` > `General` > `Privacy and data` > `Privacy settings`

There, turn on the switch for **Turn on optional connected experiences**.

![](https://cdn-assets.productfruits.com/12a89c79-f865-4b8d-84ec-5f1ccb2fecb2)

After enabling this setting, the sending of SecuMails via FTAPI will be correctly encrypted again.

## Note for administrators

In O365 environments, this setting may be disabled by organizational policies. IT administrators can control this value centrally via the Microsoft 365 Admin Center or via PowerShell.

## **Related articles**

> #### [**Outlook Add-In (new): Rollout via Microsoft 365 Admin Center**](https://support.ftapi.com/de/article/-outlook-add-in-rollout-uber-microsoft-365-admin-center)
> 
> #### [**Outlook Add-In (new): Central configuration via PowerShell**](https://support.ftapi.com/de/article/-outlook-add-in-zentrale-konfiguration-via-powershell)