How Google abbreviates things can differ from what the carrier API expects
An address issue may occur because of the Google "type ahead" address fill. Our experience is with how Google abbreviates things can differ from what the carrier API expects. For example, instead of "Saint Louis", "St Louis", or instead of "St Louis", "St. Louis". The carrier API will accept one variant, but the Google API uses another.
Reach out to Eniture Support for additional diagnostics on the issue. Be prepared to share a screenshot of the checkout/cart page of a test order presenting the issue.