Can't seem to get Tags to work

Love the plugin, so thank you for that!

I am able to get the contact info added to our Highrise account, but can’t seem to get the tags added. They show up in the notification email.

I have added a Hidden field with Field Label (under properties) with ‘tags’. And, under Advanced, I am initially just trying the tag ‘test’.

Does the tag need to already exist in Highrise? Other thoughts?

Thank you,
Evan