As you all might know, there have been few server issues recently. We have identified the bug and a patch has been released. Unfortunately, the projects have to be migrated by the user to the latest version due to major changes made in the backend part of the Builder.
The older version would be available at https://old.niotron.com
The latest version would be available at: https://builder.niotron.com
The Older Version would be up for a year allowing users to migrate in their own time. We appreciate your patience, this change was necessary for the long-term stability of Niotron.