String Function Not Working

String Function Not Working

I am trying to create a function based on the date entered into the "ITAR Expiration" field.

If the expiration field is older than 'today's date' or left blank, I want the formula to return the text 'Invalid.'

If the expiration field is a date that is in the future or today's date, I want the formula to return the text 'Valid.'

I am getting the error in the image below. Any idea what I am doing wrong? and how to fix? Thanks


If(Len(Tostring(${Vendors.ITAR Expiration}))==0,'Invalid',If(Datecomp(${Vendors.ITAR Expiration},now())/1440>=0,'Valid','Invalid'))