Delete all tax rates in WooCommerce
Sometimes you change your nexus states or you are seeing incorrect sales tax rates being applied in a state. Or perhaps you just upgraded the TaxJar WooCommerce plugin. In these situations it is sometimes necessary to remove old rates and clear the cache from WooCommerce and WordPress.
Reset WooCommerce Rates Steps:
First, make sure you are using the latest version of the TaxJar plugin.
Next, head into your Wordpress installation under the WooCommerce->System Status menu and then click on the "Tools" tab.
Find the button labeled "Delete ALL Tax Rates" and click it.
Find the button labeled "Clear Transients" and click it.
You can now test this with products in your cart.