Store Address you need to set up in Tax Settings first.
Go to Admin/Configuration/Settings/Tax Settings
Tax Based on need to be "Shipping Address"!
Note: If you have Multi-store you need to set up store country nad ZIP in all stores.
Now you need to set up Store Address in TaxCloud configuration:
Go to Admin/Configuration/Tax/Tax Providers and find Tax by TaxCloud and click configure.
Note: If you have Multi-store you need to set up store address in all stores.
Under Nop Default Tax Address add your store address and click Save
Only store and shipping address is used for TaxCloud ship to address and store address must be set.