Signals Notebook: 'Page unavailable' error when the reviewer tries to open an assigned experiment

This issue can happen if the viewing privileges for the Reviewer are not configured correctly:

1. Browse to the experiment
2. Click on the 'IN REVIEW' status and select 'Edit Reviewers…'
3. Delete the assigned reviewer by clicking the trashcan icon
4. Click on the 'IN REVIEW' status and select 'Reopen…'
5. Type an appropriate comment and click 'Reopen'
6. Click on 'Sharing'
7. From the 'Shared with:' section remove the assigned reviewer by clicking the trashcan icon
8. Log off from Signals Notebook and log back in
9. Browse the experiment click 'Sharing' and add the reviewer user again