UserName() function isn't working when shared

Hi,

I'm testing RLS, in desktop app, it works perfectly when I type in an email address.

When I Test as role in Power BI Service, worked perfectly when I typed in an email address.

When I created a content package and shared it with the email address I've been typing in, it doesn't work. May I ask why and how should i be doing this? This is a simple sql database, not an SSAS.

My DAX function 

AND ([DatabaseKey] = LOOKUPVALUE(Users[DatabaseKey], [Name], Username()), [DatabaseKey] = 1)