Abstract

Gaps in Authentication between SAP MultiBank Connectivity (MBC) and external banking gateways are becoming ever more concerning within corporate financial systems. This paper analyzes a substantial class of failures resulting from token exchange disparities, in particular, OAuth2 with mTLS+JWT tokens across numerous banking APIs within SAP’s payment ecosystem. Through a detailed examination of actual and hypothetical payment batch analyses, we demonstrate how drift in token expiry, misaligned scope boundaries, and replay prevention logic multiply authentication failures. The experiment models diverse configurations of bank-side tokens, which allow for controlled dosing of delay and misalignment, malformed payloads, and out-of-sync synchronization. Destruction of coherence was found to increase error rates in unsynchronized settings by over 600%, even with observable influence over SAP job processing queues and treasury execution pacing. Behavioral predictions of drift-based deviations using adaptive refresh algorithms demonstrated less frequent errors and reduced need for manual correction. These results point to the necessity for more effective control of issued tokens with real-time adjustment of their alignment and automated solid boundary setting for cross-gate authentication, thus establishing the basis of this research as a position of resilience in multi-bank SAP based financial ecosystems.