# Adyen: threeDS2RequestData is not supported for threeDS2InMDFlow (15_023)

**TL;DR:** You are mixing two generations of 3D Secure: the native 3DS2 request data and the old redirect (MD) flow flag. Pick one. The modern fix is to drop threeDS2RequestData from /payments and use the native 3DS2 flow end to end.

```text
15_023 - threeDS2RequestData is not supported for threeDS2InMDFlow
```

## Steps

1. **Find where the MD flow is requested.** Search your code and Customer Area settings for threeDS2InMDFlow: it can be set in additionalData on the request or as an account data setting.
   - *Success check:* you know exactly which place enables the MD flow.
2. **Remove threeDS2RequestData from /payments.** Delete the whole threeDS2RequestData object (deviceChannel, notificationURL and friends) from the request.
   - *Success check:* the request no longer contains threeDS2RequestData.
3. **Or remove the MD flow flag instead.** If you must keep threeDS2RequestData, drop the threeDS2InMDFlow flag from additionalData and disable the account setting. But the native flow is the one Adyen maintains, so prefer option 2.
   - *Success check:* exactly one of the two is present, not both.
4. **Follow the native flow steps.** IdentifyShopper for fingerprinting, ChallengeShopper for the challenge, /payments/details between steps.
   - *Success check:* the payment proceeds without 15_023.

## When to use this

- /payments fails with 15_023.
- A legacy integration was partially migrated to native 3DS2 and both flags survived.

## When NOT to use this

- You are on the redirect flow deliberately and getting other errors. Then remove threeDS2RequestData and keep the MD flow.
- 14_032 or 14_033 fingerprint errors. Those are about the details call, not the flow selection.

## Compatibility

Adyen Checkout API and classic /authorise 3DS flows.

## Why it happens

threeDS2InMDFlow routes the transaction through the old 3D Secure 1 style MD redirect flow, while threeDS2RequestData configures the native 3DS2 flow. They are mutually exclusive and Adyen rejects the combination.

## Edge cases

- The flag can hide in the Customer Area as an account data property, not just in your code. If you removed it from the request and still get 15_023, check the account settings.
- Migrating fully to native 3DS2 also means handling the fingerprint and challenge actions your redirect code never saw.