Is the prompt read from the screenshot "Butterfly and girl with watercolor feel" OK? I don't think there is anything wrong with the prompt itself. If so, it could be a case where communication with the server is not working properly or the cache on the local side is broken. Please delete your browser cache or try using a different browser.
https://status.adobe.com/cloud/creative_cloud will give you current statuses for Adobe services. Looking back in the last 7 days there were no noted issues on the Adobe server side for Firefly.