Import button in Appian Desginer is Dimmed/Disabled

Hello, 

I have previously requested a Trial Appian Cloud environment and started developing on it, and each time I exported the application I worked on, after the trial has expired I requested another trial environment, and got an access to a new one, I wanted to import the application in the new trial environment, however that time I found the  "Import" button dimmed/disabled, and currently I'm stuck.

I need to know why this time the import button is dimmed/disabled and how can I import my application to the new trial environment.

Thanks