If you are seeing this error, it means that you must return to the "GoToW Setup" tab, then click on the sub tab "Set Defaults for Opportunities". It is required that you select a value on Stage and enter a date value on Close "Date" This is a design flaw from the original version of our App. We expect this issue to be resolved in our Fall 2018 new Release.
Once you arrive to Set Defaults on Opportunities tab select a value on the "Stage" field and insert a date on the "Close Date" field.
NOTE: We are not going to affect or change either of these values on your existing or new Opportunities, unless you have configured our app to do so when you set up the GoToW Setup Lead page.