I am having issues with my Odoo e-Commerce site where taxes are not being computed correctly even if I have done the following:

1. Assign a sales tax. (12%) -- our vat rate
2. Taxes are set correctly (at the right 
3. Fiscal Position are set correctly.

How can I resolve this issue? I open the website  and this problems keeps occurring even when I use incognito mode. What should I do and what did I do wrong? A few days ago, the taxes were computing correctly and then I only changed the following

1. check track inventory
2. uncheck the continue selling when out-of-stock.

and then the prices on the products all of the sudden are not being computed with taxes.