
Just to clarify — this is a community Q&A forum, so we don't have access to your tenant or environment details and can't provision environments on your behalf. For environment creation requests, please raise that internally with your Power Platform Admin or open a support ticket with Microsoft directly.
That said, the error you're seeing is by design — Power Pages cannot be created in the Default environment that exists in every tenant. You'll need a different environment type to proceed. SPGuides
Possible solutions:
Create a Developer environment yourself (free) → Power Platform Admin Center → Environments → New → Type: Developer
Request a Sandbox environment from your Power Platform Admin for team/org use
Use a Trial environment (free, 30 days) just to get started quickly
Raise a Microsoft support ticket if you're blocked by admin restrictions or licensing → https://admin.powerplatform.microsoft.com → Help + Support
Once you have any non-default environment, switch to it from the top-right environment selector in Power Pages and site creation will work normally.
Reference:
Power Pages developer sites → https://learn.microsoft.com/en-us/power-pages/getting-started/developer-sites