Need help in writing an expression in my line graph within the measures

[Ssitharath]

Hello,

I am new in Qlik Sense. I am trying to write a function where take the average of days late to be filled and the OPT_Flag fields as "Y".

So far I have this function but it keeps giving me an error:

=Avg({<Opt_Flg={'Y'}>}Days_before_refill)

What am I doing wrong?

[Lisa_P]

Syntax looks ok, check field names are exactly the same