Troubleshooting Closed Port Error in Lindy Web App Development

Hi there, pretty new to Lindy and created a web app; however, the moment I try to download the installer and developer packages to my desktop, I get the following error: Closed Port Error | The sandbox [Name] is running but there's no service running on port 3000. I have now spent over 6000 credits trying to download and it is getting frustrating, costly, and to a point where I am about to give up. Can anyone assist? Thanks in advance. What should I do?