I have published tens of add-ons but now suddenly when doing everything the same way I get the error message "You must configure the G Suite Marketplace SDK to publish an add-on." when I try to publish an add-on using the "Deploy as Docs add-on" menu item. I have configured the "G Suite Marketplace SDK". BTW, the error dialog presenting the error message is linking to the console project correctly but the link replaces the current browser document, it would be better if it would open a new tab.