# Error handling
URL: /docs/a2a/error-handling
Catch and interpret A2A errors and error codes.
Every operation either resolves with a typed response or fails with a typed
error. On Flutter and React Native the error type is `PPA2AException`; on the
native package it is `PlusPayException`. All of them expose an **error code**
and a **message**.
| | Flutter | React Native | Native |
| ------- | ---------------- | ---------------- | -------------------- |
| Type | `PPA2AException` | `PPA2AException` | `PlusPayException` |
| Code | `errorCode` | `errorCode` | `getError_code()` |
| Message | `message` | `message` | `getError_message()` |
## Catching errors
Flutter
Kotlin
Java
React Native
```dart
try {
final result = await _pluspay.startPayment(request);
// success
} on PPA2AException catch (e) {
print(e.errorCode); // e.g. "LAUNCH_INTENT_ERROR"
print(e.message); // human-readable message
}
```
```kotlin
// Coroutine style
try {
val result = client.startPayment(request)
} catch (e: PlusPayException) {
Log.e("A2A", "${e.error_code}: ${e.error_message}")
}
// Callback style
client.startPayment(request, object : PPA2ACallback {
override fun onSuccess(result: PPStartPaymentResponseModel) {}
override fun onError(e: PlusPayException) {
Log.e("A2A", "${e.error_code}: ${e.error_message}")
}
})
```
```java
client.startPayment(request, new PPA2ACallback() {
@Override
public void onSuccess(PPStartPaymentResponseModel result) { }
@Override
public void onError(PlusPayException e) {
Log.e("A2A", e.getError_code() + ": " + e.getError_message());
}
});
```
```ts
try {
const result = await client.startPayment(request);
// success
} catch (e) {
if (e instanceof PPA2AException) {
console.log(e.errorCode); // e.g. "LAUNCH_INTENT_ERROR"
console.log(e.message); // human-readable message
}
}
```
## Error codes
Branch on `errorCode`, never on the message text. Flutter (0.8.0+) and React
Native (0.4.0+) also expose these codes as constants in `PPA2AErrorCodes`.
### Returned by the client package
| Code | Meaning |
| --------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `LAUNCH_INTENT_ERROR` | POS+ could not be launched (not installed, or the intent could not be resolved). |
| `PP-A2A-PARSE` | The response from POS+ could not be parsed. |
| `PP_A2A_015` | Another request from your app is still waiting for its result. Flutter 0.8.0+ and React Native 0.4.0+ reject the new request immediately, without launching POS+. |
| `NOT_INITIALIZED` | React Native: `initialize()` was not called before the request. |
| `TIMEOUT` | Native package: no response from POS+ within the client timeout. |
### Returned by POS+
| Code | Meaning |
| ------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `PP-A2A-003` | The intent did not contain a `request` extra. Note the hyphens: this is not `PP_A2A_003`. |
| `PP_A2A_001` | The request is empty. |
| `PP_A2A_002` | This operation needs a `data` object, but it is missing or is not an object. |
| `PP_A2A_003` | The `client_token` in the header is invalid (only checked when a token is sent). |
| `PP_A2A_004` | Invalid end-of-day request: `is_all` is `false` but `types` is empty. |
| `PP_A2A_005` | Invalid parameter request: `is_all` is `false` but `types` is empty. |
| `PP_A2A_006` | Invalid request parameter. |
| `PP_A2A_007` | Unexpected error while handling the request. The final state is unknown: query it with [`getTransactionResult` / `getOrderResult`](/docs/a2a/recovery). |
| `PP_A2A_008` | The `header` is missing. |
| `PP_A2A_009` | `transaction_type` is missing or not a known operation. |
| `PP_A2A_010` | A header field required by this operation is missing or empty (for example `order_code` or `transaction_id`). |
| `PP_A2A_011` | Nobody has ever logged in to POS+ on this device. Log in to POS+ once, then retry. |
| `PP_A2A_012` | The operation failed in POS+ (declined, cancelled by the user, order closed, …). The message describes the cause. |
| `PP_A2A_013` | POS+ could not log in automatically. Check the device's internet connection and the POS+ session. |
| `PP_A2A_014` | POS+ timed out: it could not get ready within 3 minutes, or the request did not finish within 15 minutes. The final state is unknown: [query it](/docs/a2a/recovery). |
| `PP_A2A_015` | POS+ is still processing an earlier request. Wait for that result, then retry. |
| `PP_A2A_016` | `TRANSACTION_RESULT`: the order has no transaction with the given `transaction_id`. |
`error_message` is always in **Turkish**, even when you set a
[`locale`](/docs/a2a/initialization#language). For example: *"İşlem kullanıcı
veya sistem tarafından iptal edildi!"* ("The transaction was cancelled by the
user or the system."). If you show errors to your users in another language,
map `errorCode` to your own text.
## Timeouts and concurrency
* **One request at a time.** POS+ handles a single A2A request at a time. A
second request that arrives while one is in progress is rejected with
`PP_A2A_015`. Wait for the first result before you send the next request.
* **POS+ start-up: 3 minutes.** If POS+ is launched by your request and cannot
get ready to handle it within 3 minutes, it answers with `PP_A2A_014`.
* **Request handling: 15 minutes.** If a request is not finished within 15
minutes, POS+ answers with `PP_A2A_014`. The limit is long on purpose so that
a real payment flow (card reading, PIN entry, receipt) is never cut off.
* **Client-side timeouts.** The Flutter and React Native packages don't time
out on their own. If you add your own timeout, make it **longer than 15
minutes**. Otherwise a payment that completes in POS+ looks failed in your
app.
* After it sends the result, POS+ brings your app back to the foreground and
moves itself to the background.
## Recommended handling
* Treat any thrown error as a non-completed transaction. Do **not** assume the
payment succeeded.
* For `PP_A2A_007` and `PP_A2A_014`, the outcome is unknown. Query it with
[`getTransactionResult` / `getOrderResult`](/docs/a2a/recovery) before you
retry.
* For `LAUNCH_INTENT_ERROR`, verify POS+ is installed and (Flutter) consider
providing `fallbackPackageName` / `fallbackActivityName` during
[initialization](/docs/a2a/initialization).
* For `PP_A2A_011` and `PP_A2A_013`, ask the user to open POS+ and log in.