Hi @Ratanak ,
Could you please share a bit more about your issue?
Do you want to create a Model-Driven app based on your Case Entity using PowerApps?
Which PowerApps license does your sign in account own?
Based on the issue that you mentioned, I think this issue may be related to the PowerApps license your sign in account own.
The Case Entity is an Restricted Entity in CDS within PowerApps, which has a Dynamics 365 licensing requirements for your sign in account.
If you want to create, update, or delete records within the Restricted entities using a Model-Driven app, your sign in account needs to own associated Dynamics 365 License.
Note: Actually, the Dynamics 365 Entities is based on the corresponding CDS Entities. The Entities in your Dynamics 365 would also be existed within the corresponding CDS your Dynamics 365 instance related to. Your Dynamics 365 instance is actually a PowerApps Environment.
More details about the Restricted Entity within CDS, please check the following article:
https://docs.microsoft.com/en-us/powerapps/maker/common-data-service/data-platform-restricted-entities
If you want to create, update, or delete records within your Case Entity using Model-Driven app, your sign in account must own the following license:
Dynamics 365 for Customer Service, Enterprise edition
or Dynamics 365 Customer Engagement plan
or Dynamics 365 plan
Please check if your sign in account own above appropriate Dynamics 365 license.
Best regards,
