Cannot see blocks of my app made in 2020

Hi Community,
I had made an app in my account in 2020. I tried to open it today but to my surprise, the blocks are not visible and as a result it is not working also. What could be the reason? while other apps made even before this are all present in my account with their blocks intact.

You must have made a backup of the app. Try to import this aia (backup). If there are any problems, post the aia and show the blocks.

Which server?