The hosting service in the SmartThings cloud has now been shut down for almost all groovy smartapps, including Webcore. So depending on how the UI was designed you might be able to get a few steps in, but it won’t run to completion. 
I personally think it’s more confusing to people that they left the toggle switch there, but that’s how they did it.
You may have already seen the following thread, but this is a discussion of what people are using as replacements: