Signals Notebook: No reviewers are available when user sign and review an experiment

Description Requirements: 

Standard Users from 'All Users' User group should be able to sign and review an Experiment.

System Configuration:

• User Roles settings

Make sure 'Broad User Search' checkbox for Standard User Role Name is checked:

• Security Policy settings: 

Make sure entity.write policy granted for 'All users' user group. 

• Experiment Privileges settings: System Objects-> Experiment-> Privileges

Make sure 'Sign and Close' options are checked in Experiment Privileges 

• Experiment Template is shared with 'All users' user group: System Objects-> Experiment-> Templates -> an Experiment template -> Sharing