Once I clicked on the Email Icon it displayed an error on the service builder console as:
The following errors were found:
. Value of context key mailingListIsNull is null.
Under Dashboards -> Service -> Service Builder TAB.
On the FMS a datasource issue happened. WCF datasource was not properly initialized.
We usually find ERROR in logs as: com.quest.wcf.core.datasource.QueryNotFoundException: Custom Query: wcf.is-null not found in view....
In this case the service dashboard was not able to find a query that uses, to determine if the mail recepient has been specified on the FMS. Usually restart of the FMS resolves the issue as the datasource gets loaded from the xml during the server startup.wcf uses this datasource to retrive resources needed to render dashboards.
Re-start of the FMS.
Next Time: Just in case, you come across similar/same issue, generate support bundle before re-starting the FMS & upload with the case.