Unexpected Embed Token Format and Embedding Failure

Hi NovaLee 
Thank you for reaching out microsoft fabric community forum.

The additional @odata.context property in your response is expected in some cases, though not explicitly mentioned in the documentation. The token should be used as-is without extracting any parts, even if it appears concatenated.

The "403 Forbidden" error may be due to an invalid or expired token, insufficient API permissions, incorrect embed configuration, or workspace access issues. Please verify the following:

• Use jwt.io to decode the token and check its expiration (exp).
• Ensure the accessToken used to generate the embed token has Report.ReadWrite.All permission and admin consent.
• Confirm that embedUrl, reportId, and groupId match the intended report.
• Ensure the user embedding the report has access to the workspace.

To further troubleshoot, test embedding via the Power BI Embedding Playground and validate token generation using Postman or another API tool.
I've attached the Microsoft documentation that might be helpful to you.
Generate an embed token in Power BI embedded analytics - Power BI | Microsoft Learn
Troubleshoot Power BI REST APIs - Power BI | Microsoft Learn

If this solution helps, please consider giving us Kudos and accepting it as the solution so that it may assist other members in the community.
Thank you.