QuickBooks Payments applies different rules to credit card transactions that are placed within QuickBooks Online compared to transactions that processed through their API by third party apps like Novi AMS.  This is why a credit card could be labeled as "invalid" in Novi yet process without issue inside of QuickBooks Online.

The difference is due to different "AVS Settings."  "AVS" stands for "Address Verification System," and the settings live up to their name.  Novi AMS makes no recommendation as to what your AVS Settings should be, but we're happy to show you where to make changes.