Hi @ronaldhon ,
Do you want to restrict one Web Page for only authenticated user?
Based on the needs that you mentioned, I think the "Web Page Access Control Rule" in Portal Management could achieve your needs.
More details about the "Web Page Access Control Rule" in Portal Management, please check the following article:
https://docs.microsoft.com/en-us/powerapps/maker/portals/configure/webpage-access-control
On your side, please try the following steps:
1. Go to your Portal Management
2. Switch to "Web Page Access Control Rule" option, then click "New" button to create a new page access control rule.
3. Switch to "Web Roles" tab or click "Related"-> "Web Roles" option, to bind "Authenticated Users" web role to this control rule:
4. You need to assign the "Authenticated Users" Web Role to proper Contacts in your current portal site.
5. Edit your PowerApps Portal, click "Sync Configuration" button in your Portal designer to apply the changes you made in your Portal management, then click "Browse website".
Note: The "Web Page Access Control Rule" must be bind to a specific Web Role, then these contacts assigned with this "Web Role" could apply the "Web Page Access Control Rule"
Please also check and see if the following blog would help in your scenario:
https://readyxrm.blog/2019/08/26/powerapps-portals-how-to-hide-or-show-content-based-on-logged-in-user/
Best regards,
