NATURALLEFTOUTERJOIN producing no common column error

Hey all 

Getting an error with the below DAX - NATURALLEFTOUTERJOIN requires at least one common join column. As you can see, I have EMAIL in both Tables ... each table will evaluate and produce correct results within it's own context without error so that's not the issue per se (though there maybe something in the details causing my problem obviously).  I am doing this in DAX Studio because eventually I need it in a Power BI Report Builder report outside of Desktop. 

I see something from Marco about breaking data lineages (https://www.sqlbi.com/articles/from-sql-to-dax-joining-tables/) but I don't understand how to apply it to my scenaro.

Any help would be appreciated. 

Danielle

DEFINE 

    TABLE AE_EMAILS = 
        SELECTCOLUMNS(
            FILTER (
                SUMMARIZECOLUMNS(
                    Cleanup[EMAIL_VALIDATION]
                ),
            [EMAIL_VALIDATION] <> BLANK()
            ),
        "EMAIL", [EMAIL_VALIDATION]
            )
        
    TABLE SYSTEM_INFO = 
        SELECTCOLUMNS(
        
            SUMMARIZECOLUMNS(
                SYSTEM_USERS_ALL[Active],
                SYSTEM_USERS_ALL[User Role],
                SYSTEM_USERS_ALL[License Type],
                SYSTEM_USERS_ALL[Username]
            ),
                
        "EMAIL", [Username],
        "ACTIVE", [Active],
        "USERROLE", [User Role],
        "LICENSETYPE", [License Type]
        )
    
EVALUATE NATURALLEFTOUTERJOIN (AE_EMAILS, SYSTEM_INFO)