CoPilot - Prep Data for AI

Hi dgwilson​,

Here looks like the issue is related to the network/proxy configuration rather than the power bi permissions. The same report and user can access Prep Data for AI when connected to the office network and it fails from home. The home network is likely blocking one of the connections used by Prep data for AI and then incorrectly displays the generic error message.

Please work with your network team to check the proxy or vpn configuration and the outbound connections from power bi desktop.If the issue continues, raise a Microsoft Support ticket with the desktop version, proxy or vpn configuration details and the timestamps from a failing attempt so that the team can identify the specific request that is failing.
Create a Fabric and Power BI Support Ticket - Power BI | Microsoft Learn

For reference, follow the below documentation:
Add Power BI URLs to allowlist - Microsoft Fabric | Microsoft Learn
Troubleshoot sign-in issues in Power BI Desktop - Power BI | Microsoft Learn

Thanks and regards,
Anjan Kumar Chippa