Signals Notebook: I can't find a reviewer in the Sign and Add Reviewers window

Details:  The reviewer exists in the tenant but it is not shown when searching for it in the 'Sign and Add Reviewers' window. 

Solution:

1. Ensure you have shared the experiment with the user or the group the user belongs to before attempting to send the request. The list will only show users you have shared the experiment with as possible reviewers.

2. Search using the full e-mail address. If the user is not in the same domain and 'Broad User Search' is not enabled for your user role it will not be displayed without using the full e-mail address for searching.