Mac users can't release messages from Exchange Online Protection quarantine

Original KB number:   2909418

When a user tries to release a message from the Exchange Online Protection quarantine when using the Safari browser on a Mac, the user is prompted for a certificate as follows:

The website "na01-quarantine.dataservice.protection.outlook.com" requires a client certificate.

To resolve this issue, follow these steps:

1. Locate the Keychain Access program on the Mac. To do this, open Finder, and then open the Applications folder. The Applications folder contains a folder that's named Utilities. The Keychain Access program is in the Utilities folder.
2. Open Keychain Access, and then locate all certificates in the Safari dialog box that show as This client requires a certificate.
3. Select the certificates that you located in step 2, and then delete them from Keychain Access.
4. Restart Safari.

Third-party information disclaimer

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