We are aware of this issue as of a few hours ago. This is affecting Sortd and most other Gmail applications.
Gmail has released some new features as a result of the Google Cloud Next Conference that took place a week ago. They have changed the information that they are sending us and we are working on a fix.
We have included some short-term workarounds below.
This seems to be primarily affecting users who have Gmail Reading Pane enabled. We recommend that you temporarily select "No split". Alternatively, you can work in Sortd's full screen view which has its own split view.
You may also notice that these blue Sortd buttons above the inbox are not working correctly with the Reading Pane active (Right of inbox or Below inbox is selected).
If you are in Gmail view and you want to add an item to the board, you can also select a mail and add it to the board as follows (if you want to keep the Reading Pain on):
Please let us know if you see anything else out of the ordinary. Contact us at firstname.lastname@example.org