Hello Mimoun Mendoughe,
As per the description, we understand that you are not able to assign an owner for recommendations in Defender for cloud and when tried with governance rule, it fails. Administrator is also has facing the same issue.
To review recommendations, you must enable Defender Cloud Security Posture Management (CSPM) on your environment.
Note : Recommendations are included by default with Defender for Cloud, but you can't see risk prioritization without Defender CSPM enabled on your environment.
When Defender for Cloud performs a risk assessment of your security issues, the engine identifies the most significant security risks while distinguishing them from less risky issues. The recommendations are then sorted based on their risk level, allowing you to address the security issues
Recommendations are included with the Foundational CSPM plan which is included with Defender for Cloud. However, risk prioritization and governance is supported only with the Defender CSPM plan.
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