Encountering an error: Please enter a value for email When Adding a Group as an Email Recipient

1. Create an Email from a Transaction or from an Entity record.

E.g.
1.1. From a transaction record:
1.1.1. View a Sales Order.
1.1.2. Navigate to Communication > Messages tab > click on Email button. 


From an Entity:
1.2. From a customer record:
1.2.1. View a customer record.
1.2.2. Navigate to Communication > Messages tab > click on Email button.


Email pop-up appears, from recipients tab, the recipient automatically populates the customer associated to the transaction. Under Copy Others , selected the name of the group that should be copied in the email. Click Done button.
An error will be encountered: Please enter a value for Email.

2. If said error is encountered it means, the group doesn't have an email specified from the main section.
3. To check this navigate to Lists > Relationships > Groups.
4. View the group that was added in the email earlier.
5. Check the email field from the main section. Add an email for the group.
6. Navigate back and add the Group Name to an email and it should resolve the issue.

Note: Group email should be specified if users want to set a Group for an individual email through a Transaction or Entity record. However, for Bulk emails and Campaigns, users may skip on setting a single email for the entire group.