Hi @haryadihart ,
As @ragavanrajan described there are two types of the data model for the power pages (Standard data model & Enhanced data model).
If your environment is a newly created one then you will find by default the Power Pages model driven app.
You will not be able to migrate your portal from the old environment to the new one because as mentioned they are two different types of the data model.
Now you have two solutions:
1-The hardest one: At the old environment you have to repeat all configurations from the Portal management to to the Power Pages management, then you can migrate your website to the higher environment.
2-The second solution is disabling the enhanced data model on the new environment and do the next steps:
a- after disabling the enhanced data model wait from half hour to one hour to let Microsoft installing all needed packages for the Standard data model.


b- After Microsoft completes the installation then you will be able to see the model driven app for the Portal Management.
c- Now you can create new website based on the standard data model, then migrate your website from the old environment without any issues.
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