Obtaining the Power BI Report Server Developer Edition?

I need to upgrade our Power BI Report Server in our DEV environment. When I run setup, I can only choose the option to install into production (requiring a product key- but I do not have one as this server is in our DEV environment). If I select either the 180-day trial or the developer edition the 'Next' button remains disabled and I cannot continue setup.

Does anyone know why this behavior might be occurring? Am I installing the wrong version? 

Thank you kindly for any help or insight.