First, determine the program that taxes are not applying for.  If you are using a Daily Sales button, do this to find the program:
  1. Go to Tickets > Configure Daily Sales.  
  2. Find the name of the button here.
  3. Click on the button and click Edit.
  4. Note the program name here. 
Now, add taxes to the program.
  1. Go to Tickets > Program Search.  
  2. Open the program for which taxes are not applying.
  3. Go to the Fees/Taxes tab.
  4. See there is no tax defined here.
  5. Add tax.