What specific diagnostic data point originating from the client application is most valuable for remotely troubleshooting an 'OTP token mismatch' error reported by the server?

The most valuable specific diagnostic data point originating from the client application for remotely troubleshooting an 'OTP token mismatch' error reported by the server is the client's precise system timestamp at the moment the One-Time Password (OTP) was generated. This is particularly crucial for Time-Based One-Time Password (TOTP) systems, which are widely used. TOTP algorithms rely on both the client and server having synchronized clocks. If there is a significant 'time skew'—a difference in the reported time—between the client's device and the server, the OTP generated by the client will not match the OTP the server expects based on its own time. By comparing the client's reported timestamp with its own, the server can determine if a time synchronization issue is the cause of the mismatch, as it can recalculate what the OTP *shouldhave been if generated at the client's reported time. While less common, if the OTP system utilizes an HMAC-Based One-Time Password (HOTP) algorithm, the most valuable data point would instead be the client's exact internal counter value used during the OTP generation, as HOTP depends on a synchronized event counter rather than time.