# Neptune Streams API Exceptions
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The following table describes Neptune Streams exceptions.


| Error Code | HTTP Code | OK to Retry? | Message | 
| --- | --- | --- | --- | 
| `InvalidParameterException` | 400 | No | An invalid or out-of-range value was supplied as an input parameter. | 
| `ExpiredStreamException` | 400 | No | All of the requested records exceed the maximum age allowed and have expired. | 
| `ThrottlingException` | 500 | Yes | Rate of requests exceeds the maximum throughput. | 
| `StreamRecordsNotFoundException` | 404 | No | The requested resource could not be found. The stream may not be specified correctly. | 
| `MemoryLimitExceededException` | 500 | Yes | The request processing did not succeed due to lack of memory, but can be retried when the server is less busy. |