I have taken free trial subscription of Office 365 Enterprise E3 and added a site as a developer site. Then I added an app which is a SharePoint add-in and tried to publish it using Napa online. But while doing so it's giving me an error as below
I'm having the same issue since yesterday. Sometimes it works for a few hours, then it doesn't.
Other users report the same problem:
So it seems that Microsoft messed something up. Let's hope they can fix it quick.