I was editing my project in Kodular Creator when the editor suddenly displayed this error. The project did not load correctly and the technical information showed projectId = -1. The error occurred while opening or editing the project in the Designer/Blocks area. I am using Chrome on Windows 10.
Sometimes it happens when platform faces an error or blocks are so many it cannot handle, you need not to worry about it, just reload the project and use it and next make sure to keep a backup copy of your project and also keep an eye at what caused the error and if this error arises next time as well while doing the same kind of stuff then avoid doing that and try to find another alternate.