User with HR role is not able to use Email UI action.
popupOpenEmailClient(URL) function is being used in Email UI action which is not working.
Customization of OOTB ACL:
The UI action is using function popupOpenEmailClient(url);
This is an internal script to display a standard email sending popup: popupOpenEmailClient().
When using this feature, we need to allow these users of the application on an ACL named: EmailClientProcessor.
Activate OOTB for EmailClientProcessor
This ACL will allow user with HR writer role to use Email UI action.