Help Writing Conditional Rule for Field

**I am using Adobe Acrobat DC**

Hi, I am having issues writing a conditional rule for a field.  As a guide I am using the help article referenced in the hyperlink below.  Navigate to Specifying Conditional Rules for Fields.

https://helpx.adobe.com/sign/using/text-tag.html#TextTagsDeepDive

I have a field called t045_Owner 1 First Name and I only want this field to show on my form if field d08_7 is checked.  My formula is below.

t045_Owner 1 First Name_es_signer1:showif(d08_7=checked)

The result of this of this formula is that the field t045_Owner 1 First Name always shows on the form regardless of whether box d08_7 is checked.  Please help me.