1# Motion Awareness Error Codes 2 3> **NOTE** 4> 5> This topic describes only module-specific error codes. For details about universal error codes, see [Universal Error Codes](../errorcode-universal.md). 6 7## 31500001 Service Exception 8 9**Error Message** 10 11Service exception. Possible causes: 1. A system error, such as null pointer, container-related exception; 2. N-API invocation exception, invalid N-API status. 12 13**Symptom** 14 15This error code is reported if a service exception occurs when the **on**, **off**, or **get** API of the motion module is called. 16 17**Possible Causes** 18 19The service status is abnormal. 20 21**Solution** 22 231. Retry the operation at a specified interval (for example, 1s) or at an exponential increase interval. 242. If the operation fails for three consecutive times, stop the retry. You can also attempt to obtain the sensor list to check for device availability. 25 26 27 28## 31500002 Subscription Failed 29 30**Error Message** 31 32Subscription failed. Possible causes: 1. Callback registration failure; 2. Failed to bind native object to js wrapper; 3. N-API invocation exception, invalid N-API status; 4. IPC request exception. 33 34**Symptom** 35 36This error code is reported if subscription fails when the **on** API of the motion module is called. 37 38**Possible Causes** 39 40Subscription to change events has failed. 41 42**Solution** 43 441. Retry the operation at a specified interval (for example, 1s) or at an exponential increase interval. 452. If the operation fails for three consecutive times, stop the retry. 46 47 48 49## 31500003 Unsubscription Failed 50 51**Error Message** 52 53Unsubscription failed. Possible causes: 1. Callback failure; 2. N-API invocation exception, invalid N-API status; 3. IPC request exception. 54 55**Symptom** 56 57This error code is reported if unsubscription fails when the **off** API of the motion module is called. 58 59**Possible Causes** 60 61Unsubscription from change events has failed. 62 63**Solution** 64 651. Retry the operation at a specified interval (for example, 1s) or at an exponential increase interval. 662. If the operation fails for three consecutive times, stop the retry. 67