Applies to Event Management & Employee Training Management

SharePoint | sapiens – ACS Retirement on April 2, 2026: App Stops Working (How to Fix)

Overview

On April 2, 2026, Microsoft retired the legacy Azure Access Control Service (ACS) authentication model used by classic SharePoint add-ins.
Because our products (Event Management, Employee Training Management, and Calendar Email Extension) previously relied on ACS, all customers still using the legacy add-in version experienced immediate outages once Microsoft disabled ACS.

Most customers completed the upgrade to the modern Microsoft 365/Entra ID App model ahead of time, ensuring uninterrupted service.
However, if your organization did not complete the upgrade, your app is now failing due to the retirement.

This article explains:

• What the ACS retirement means

• The notifications we provided

• How to recognize that your app is affected

• How to fix the issue and restore functionality

 Hundreds of Successful Customer Upgrades

By early 2026, hundreds of customers had already completed the upgrade successfully.
The upgrade process is:

• Extremely smooth

• Fully automated

• Completed within seconds (requires Global or Application Administrator)

• Zero downtime

• Nothing changes for users on the SharePoint site — all data, settings, lists, and URLs remain fully intact.

Notifications Sent to Customers

To ensure organizations had ample time to prepare, we communicated the required upgrade through multiple channels long before the retirement date.

In‑App Notification Banner (Visible Since Q2 2024)

Starting in Q2 2024, all site owners consistently saw an in-app banner inside the SharePoint | sapiens backend settings, notifying them of:

• The upcoming retirement of the ACS authentication model

• The requirement to upgrade to the Microsoft 365 App model

• A direct, one-click Upgrade now link for administrators

This banner remained visible until the upgrade was completed.

February 5, 2026 — Email Notification

Customers that were still using the add-in were informed that:

• Microsoft would retire ACS on April 2, 2026

• All SharePoint add-ins based on ACS would stop working

• An upgrade was required to avoid service disruption

Detailed step-by-step instructions were included.

March 12, 2026 — Email Reminder

A personal follow-up was sent to tenants still using the old add-in model, reiterating that:

• Their installation had not yet been upgraded

• The app would stop working after April 2, 2026

• The upgrade required only a few seconds from an administrator

How You Will Notice the Issue

If your app stopped working after April 2, 2026, and you have not completed the upgrade, you will see one or more of the following symptoms:

1. The app is no longer functioning

You may notice:

• App-generated emails are no longer being sent

• Enrollments or registrations are no longer processed

2. Error messages appear on your SharePoint site

You may see:

The SharePoint | sapiens app is unable to send emails. Please contact your administrator.

or

The SharePoint | sapiens app is unable to send emails. Please verify the app settings.

3. Backend access errors

Opening the backend settings will result in an error, preventing access to configuration pages.

These errors indicate the app is still running on the now-retired SharePoint add-in authentication.

 

How to Fix the Issue (Immediate Resolution)

To restore functionality, you must complete the upgrade to the Microsoft 365 App model.
This is the same upgrade offered in the in-app banner and email notifications.

Step 1 — Open the SharePoint | sapiens Backend Settings

You can access the backend in multiple ways:

Option A: Through Site Contents

• Open the SharePoint site where the app is installed.

• Go to Site Contents.

• Select one of the following apps:
  
   

Option B: Through a Sapiens List

• Open any Sapiens list, for example:
  
   

• Click Sapiens App Settings in the command bar.

Option C: Through the “For Administrators” page

• Open the For Administrators page inside the app.

• Click Open app settings.

Step 2 — Click the Upgrade Link in the Yellow Notification Banner

When the backend opens, you will see a yellow notification banner explaining that the classic add-in no longer works.

Click Upgrade now (or the equivalent upgrade link).
This starts the automated upgrade.

Step 3 — Grant Required Permissions

You must be a:

• Global Administrator, or

• Application Administrator

in your Microsoft 365 tenant.

Follow the prompts to grant the updated permissions for the modern app model.
The upgrade completes within seconds.

For more details, read this article.

After the Upgrade

Once complete:

• All features resume normal operation

• Emails, workflows, and enrollments begin running again

• The legacy add-in version is automatically replaced or removed

If remnants of the old add-in still appear in Site Contents, you may delete them manually.

After cleanup, only one app should remain:

✔ SharePoint | sapiens Modern User Interface

We also recommend updating the Modern UI app to the latest version for best performance.

Need Help?

If you are unable to access the backend, do not have the required permissions, or need direct support:

Contact SharePoint | sapiens Support
or
Reply to any previous notification email — we are happy to assist.