If there are two or more fields for the CC, TO or BCC fields on a workflow for an "Email Event" and just one of those values is left blank when it is populated from a form, it results in an error:
"The email address, Null or Empty, does not meet the requirements." 
The email does not get sent.

Email Event:


Management Error:


The workflow will result in an error if one of more values are left blank in "CC, TO, or BCC" for an "Email Event" when the values are populated from a form.


A workaround was created where the "Split" function is used to put multiple references in, separated by a semi-colon ";" between the values and then have the separator be a semi-colon ";".
This will allow for the fields to be empty for one or more values and still be able to send/receive the email.

Split Function: