Hey Stephen,
When looking this up I found that Atlassian is already aware of the issue and has The Trello for Gmail add-on fails to work open to investigate. You can go here, log in, vote and watch it for future updates.
The latest update is:
Hey everyone, I know you're all eager for an update. This add-on hasn't been updated in recent years, and, in investigating the problem, it became clear that there were a lot of backend issues that needed updating. Ultimately a migration to a different backend system was the best solution for future stability and better future technical support. This migration requires new approvals both from within Atlassian and from Google, and that's the stage we're in now. These approvals can take some time to work through, but we're close to the finish line.
In the meantime, you can use the board email address to continue creating Trello cards from your messages in Gmail: https://support.atlassian.com/trello/docs/creating-cards-by-email/
Hope this helps!
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.