If you have Log API Response Details checked:

You will probably see something like:

odoo.addons.account_avatax.models.avatax_rest_api: Response
{'address': {'city': 'Irvine ',
             'country': 'US',
             'line1': '400 Michelson Dr',
             'postalCode': '92612',
             'region': 'CA',
             'textCase': 'Mixed'},
 'coordinates': {'latitude': 33.667281, 'longitude': -117.842675},
 'messages': [{'details': 'The address was found but the street number in the '
                          'input address was not between the low and high '
                          'range of the post office database.',
               'refersTo': 'Address.Line0',
               'severity': 'Error',
               'source': 'Avalara.AvaTax.Common',
               'summary': 'The address number is out of range'}],
 'resolutionQuality': 'NotCoded',
 'validatedAddresses': [{'addressType': 'UnknownAddressType',
                         'city': 'Irvine',
                         'country': 'US',
                         'latitude': 33.667281,
                         'line1': '400 Michelson Dr',
                         'line2': '',
                         'line3': '',
                         'longitude': -117.842675,
                         'postalCode': '92612',
                         'region': 'CA'}]}

Essentially, you must provide an address that the USPS database will validate or bypass the validation.

Review the Avalara documentation which states:

Using an unvalidated address affects the accuracy of the tools we use to determine where you need to collect tax, which can affect your returns filing. If you use this address, look carefully at where you're set up to collect and remit tax and manually add any missing tax authorities.

You can mark the address with the terms General Delivery by following the methods outlined in \https://help.avalara.com/Frequently_Asked_Questions/Addresses_FAQ/Can_I_use_General_Delivery_when_an_address_will_not_validate%3F?origin=deflection

Avalara has a great tool for checking an address in isolation of Odoo:

The TAX CALCULATOR Menu will exercise the API just the way Odoo would, so you can check here if a particular address will validate and what the expected rate would be.