Microsoft Power Platform requires some of the URLs that are to be configured in the Firewalls or need to add them in your browser proxy settings to access them.
If the endpoints are not configured properly, this will have an impact on accessing the Power Platform services or some features might not be loaded in Power Apps, Dataverse, Dynamics 365 etc.
Follow the below links and configure to access all the resources without any issue in your restricted or secured environment.
URLs for Power Platform services
URLs for Dynamics 365 services
Hope you have configured all the URLs and accessing all Power Platform services seamlessly.
My earlier articles related to Dynamics 365 CE that you can have a look and share your feedback.
How to disable Multi-Factor Authentication (MFA) on Dynamics 365 Login?
How to Create Microsoft Power Apps 30 days Online Trial Version and an Environment?
How to Update the URL of the Dynamics 365 CE Environment?
Power Apps US Government service URLs
How to Download Microsoft Power Platform Icons?
Microsoft Dataverse and Postman articles
Microsoft Dynamics 365 Online regions list
How to Install, Connect to Microsoft Dataverse and Use XrmToolBox?
How to take the Back-Up of Dynamics 365 Online environment?
How to restore Database Backup in Dynamics 365 Online?
How to recover a deleted Environment in Dynamics 365 CRM Online