We have developed a Gmail Add-On that we only use internally within our company. Yesterday our employees were able to install the Add-On following the steps on this help doc:
https://developers.google.com/gmail/add-ons/how-tos/install-unpublished
Today this no longer works. When the user clicks the "Authorize Access" button a window pops up with an error.
The code for the add-on has not changed at all from yesterday to today.
For those who already had access to the Add-on, they noticed a few changes to the UI of the Add-on (ie. CardHeaders with empty strings are now collapsed). This seems to suggest that an update was made to the Gmail Add-On platform today. I wonder if the update today broke the authorization process for unpublished add-ons?
In my experimentation, it looks like when I install a Gmail Add-On from the G Suite Marketplace the "authorize scopes" screen is now part of the install process. The initial "Authorization required" card for the installed Add-On no longer appears. So it definitely seems like the authorization flow was changed, but maybe not updated for unpublished apps? Can this be investigated please?
I should also mention we are working on creating a new add-on to publish on the G Suite Marketplace and right now it is impossible to build and test it without being able to deploy it locally.