I'm currently trying to delete the oldest backup version  for one of my apps in order to create a new backup but when I click to delete it nothing happens.  Also for the same backup version when I click download I get an error page:

"An error has occured. It has been reported to Zoho Creator support. We will look into this issue .
Sorry for the inconvenience caused."

I can download all other backups and I would assume I can delete the others although I do not wish to delete them yet.

Thanks for your help