Can a TN Visa Be Denied?

Absolutely. A TN visa applicant can be denied under the following conditions: 

1. Their credentials don’t match the qualifications for TN visa status 
2. Prior U.S. immigration violations while visiting the U.S. 
3. Lack of required documents at the border 
4. USCIS believes that you have “immigrant intent” and desire to live in the U.S. permanently