Hi John, my name is George from Okta Support. In order to troubleshoot an issue with Gmail, you can check the following: 1. Dashboard tasks If the user does not have the G Suite application assigned to them this may be caused by a provisioning issue depending on the case. To access the tasks section from your Okta Admin panel click on Dashboard -> Tasks -> Search for the person affected by the problem. 2. Check the system log for any errors. You can access the system log by going to Reports -> System log. In this section you can check for errors by filtering the report by date, user and application name and entry category. 3. Lastly, if this is an issue with only one user that previously had access to Gmail and nothing changed in Okta you I would also recommend to investigate his account in Gmail in case the account is disabled or the access is restricted.
If none of the above steps help, please do not hesitate and open a support ticket(by using the button on the top right side) for further assistance.