Internal Emails Missing from Investigate & Respond

Today, April 8th 2026, between 14:31 and 14:48 UTC, we experienced an issue impacting the visibility of Internal Emails in the Investigate & Respond tab of Core Email Protection API. Impact: • All emails received, sent internally, April 8th 2026 between 14:31 and 14:48 UTC. • These emails were successfully checked by Core Email Protection API. • If it triggered detection, a Security Event was successfully created and can be found in your portal. • Any associated remediation actions, such as Warn or Quarantined according to your configuration, were successfully actioned. • If you attempt to search for these internal emails in Investigate & Respond, it will not return any results. • External emails, or internal emails outside the impact window, will still show in I&R. The team took quick action to alleviate the issue and minimize the impact window. After thorough investigation, we've determined we will not be able to restore the missing emails. Proofpoint will continue to monitor closely overnight.