Error when using Banana 2.5

IME that’s not an especially useful error message.  I am reasonably sure that I have encountered it when I have got the process a bit wrong.  It’s one of those ‘can’t prove a negative’ situations — who’s to say that the server was having a tantrum and it would have worked the next time regardless.

To have the best chance, make sure you have everything right. Have you made a selection? Do you have a suitable layer selected? Are you using the appropriate Ai model?

I have attached a useful cheat sheet from The Photoshop Cafe.