Troubleshooting Data Loss Prevention solution - Policy Tip and Acknowledgement Override Not Work

DoveLamb 0 Reputation points
2026-09-10T00:16:33.8933333+00:00

Setting up a DLP in Purview to monitor PII Social Security Numbers when end-users are emailing via EXO to user outside organization. Setup to block users outside organization with policy tip to end-user with notice to make them aware this is sensitive data as well as acknowledgement override BEFORE sending email. Tested and email does not prompt with policy tip nor show options to acknowlege before sending. Neither configurations work. Please advise.

Microsoft Security | Microsoft Purview

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  1. Mathias Baden 0 Reputation points
    2026-09-10T09:40:57.9433333+00:00

    A few things to check first:

    • Does the user have a license that covers DLP? (Business Premium, E3, E5, etc.)
    • Make sure you're testing with valid input that actually matches the SIT.

    For troubleshooting, set up this config:

    Create the DLP policy, select Exchange Online, and scope it to your test user. Follow the images below for the config.

    I've seen many times that the policy tip doesn't show. A good first way to test the DLP itself is by enabling the email notification — then you know the DLP actually matched.

    dlp1

    dlp2

    Test in Outlook on the web first, then test in the desktop app.

    I had this issue at a client a couple of years ago — this doc is also worth a check: https://learn.microsoft.com/en-us/troubleshoot/microsoft-365/purview/data-loss-prevention/data-loss-prevention-policy-tips#dlp-policies-in-exchange-online 🙂

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