If you have been working within the Form Builder for an extended period of time, it is possible for your browser to time out and thus lose its connection to GoCanvas. If that is the case, you can often re-establish that connection by following these steps:
1. DO NOT close or navigate away from the the Form Builder (or the window the Form Builder is open in).
2. Open a new tab in the same browser and navigate to gocanvas.com.
3. Log out of GoCanvas in that window.
4. Log back into GoCanvas.
5. Return to your original window and Save.
As a best practice, save your work periodically while working in the Form Builder.