Need to manually synchronize the Cloud's Auth Connector username database to reflect new changes in the Active Directory.
The Web Security Service responds reasonably quickly to new AD integrations. After that, the Web Security Service automatically performs an AD refresh once a week to poll for newly added users. Group memberships are identified through a different process, however. The Web Security Service re-queries group membership every 15 minutes (for active log-ins and users who are already authenticated).
Be advised that it might take up to 24 hours to see the information in your portal. Avoid re-clicking the button more than once in a 24-hour period; doing so might overly clog the sync queue, causing slower results.