This is a Google/Gmail issue. We have reported it to them and are still waiting for a reply. Being that it has been awhile since we have an update from Google, we decided to write up this short article with a workaround below:
There is an infrequent issue where you may get an error "The state token is invalid or has expired. Please try again" when accessing the Gmail Add-on:
This may happen when you:
1. Install the Gmail add-on or Chrome Extension and give OAuth permissions to Sortd/Gmail
2. Revoke Sortd's permission to Gmail via Google Account manager.
Step 1. Open a new browser tab in Incognito mode and open Gmail (on your desktop or laptop)
Step 2. Open any email from your Inbox
Step 3. Click on the Sortd Add-on squirrel icon on the right bar
Step 4. Click get started
Step 5. Click the small link highlighted at the bottom "Activate the Gmail add-on here" below the red button.
You should then see a message to say "Success"
You can then close then try close the Incognito tab and try it again on mobile.
If you continue to have problems, please contact firstname.lastname@example.org and please reference this article.