1# Network Connection Management 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## 2100001 Invalid Parameter Value 8 9**Error Message** 10 11Invalid parameter value. 12 13**Description** 14 15This error code is reported if the parameter value is invalid. 16 17**Cause** 18 19The input parameter value is not within the valid value range. 20 21**Procedure** 22 23Check whether the input parameter value is within the valid value range. 24 25## 2100002 Service Connection Failure 26 27**Error Message** 28 29Failed to connect to the service. 30 31**Description** 32 33This error code is reported if a service connection failure occurs. 34 35**Cause** 36 37The service is abnormal. 38 39**Procedure** 40 41Check whether system services are running properly. 42 43## 2100003 System Internal Error 44 45**Error Message** 46 47System internal error. 48 49**Description** 50 51This error code is reported if a system internal error occurs. 52 53**Cause** 54 551. The memory is abnormal. 56 572. A null pointer is present. 58 59**Procedure** 60 611. Check whether the memory space is sufficient. If not, clear the memory and try again. 62 632. Check whether the system is normal. If not, try again later or restart the device. 64 65## 2101007 Callback Not Exist 66 67**Error Message** 68 69The callback does not exist. 70 71**Description** 72 73This error code is reported if a **callback** object to be unregistered does not exist. 74 75**Cause** 76 77The **callback** object has not been registered for activating a network or listening to network status changes. 78 79**Procedure** 80 81Before unregistering a **callback** object, make sure that it has been registered for activating a network or listening to network status changes. 82 83## 2101008 Callback Already Exists 84 85**Error Message** 86 87The callback already exists. 88 89**Description** 90 91This error code is reported if the same callback already exists. 92 93**Cause** 94 95The **callback** object has been registered for activating a network or listening to network status changes. 96 97**Procedure** 98 991. Check whether the **callback** object has been registered. 100 1012. If the **callback** object has been registered, use the registered **callback** object. 102 103 104## 2101022 Number of Requests Exceeding the Maximum 105 106**Error Message** 107 108The number of requests exceeded the maximum allowed. 109 110**Description** 111 112This error code is reported if the number of network requests exceeds the maximum. 113 114**Cause** 115 116The number of requests for activating a network or listening to network status changes has reached the maximum value. 117 118**Procedure** 119 120Locate the fault based on the "Over the max request number" log record. 121