Welcome to the Microsoft Q&A forum
It seems like you're encountering issues with starting a Purview Solutions Trial despite meeting the requirements.
Please check the below steps and confirm us:
From your company:
- Licensing Requirements: Ensure that the accounts you're using meet the licensing requirements. For Purview Data Loss Prevention (DLP), the required licenses include Microsoft 365 A1/E3/A3/Business Office 365 E3/A3 for DLP for Exchange Online, SharePoint Online, and OneDrive for Business1. For Teams DLP, Microsoft 365 E5/A5 is required.
- Role and Permission Assignments: Verify that the roles assigned to the accounts have the necessary permissions. The roles that can start or end a trial include Billing Administrator, Compliance Administrator, Compliance Data Administrator, and Global Administrator.
- Purview Portal: Make sure that the Purview portal supports directly managing permissions for users who perform compliance and security tasks in Microsoft 365.
From the Web:
- Eligibility and Licensing: The Microsoft Purview solutions trial is available for Microsoft 365 E3, Office 365 E3, and Enterprise Mobility and Security E3 customers who don't already have a Microsoft E5 license package. The trial isn't available for Microsoft 365 Government customers
- Starting the Trial: Sign in to the Microsoft Purview portal. On the home page, go to the Trials and recommendations section and select View all trials and recommendations. In the Purview and Priva trials section, find the Microsoft Purview solutions card and select Try now. If you close out of the flyout pane without starting a trial, you can view the Microsoft Purview trials cards and information. Find the Microsoft Purview solutions card and select Try now to start the trial.
- Roles for Starting the Trial: A user with one of the roles listed above can start or end a trial. Microsoft recommends using roles with the fewest permissions to improve security.
I hope the above steps will resolve the issue, please do let us know if issue persists. Thank you