The plugin appears to be very broken.
I was experiencing the same problem as OP. Did as suggested and disconnected my account. Bad move, now I can’t access any of my forms. After successfully linking my account and entering my client ID and secret I don’t get any of the other menu options.
The only option is to connect my account all over again?
Have also tried uninstalling and re-installing the plugin. No good.
How do I get a copy of an older version??