We have an organization of 900 users. We are using Jira Service Desk and trying to setup access for approximately 850 of these users as Portal Only Customers. We have setup user provisioning utilizing Azure AD and Atlassian Access and all users have synced with no issues. The entire user base has been added to a specific Service Desk Project as portal users. Our Service Desk Agents have no issues logging in using SSO, but new users that have been synced get the following error when using SSO for the Service Desk Portal.

The user provisioning documentation says that "You can activate a user's Atlassian account from the identity provider", but I cannot figure out how to do that.
Any suggestions?