ESP 32 gatt client连接ble设备注册NOTIFY无效的问题

[某某ESP32友]

ESP32，IDF版本5.1.2。连接某一ble设备，版本据说是5.0，没法验证，通过手机BLE调试APP操作反应正常，其通知和写特征值是分开的，注册NOTIFY服务后，写入成功后，设备会自动应答，但NOTIFY动作无反应。

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I (7578) GATTC_DEMO: ESP_GATTC_CONNECT_EVT conn_id 0, if 3
I (7578) GATTC_DEMO: REMOTE BDA:
I (7578) GATTC_DEMO: 25 79 62 57 60 74[attachment=0]gattc_demo.c[/attachment]
I (7578) GATTC_DEMO: open success
I (8208) GATTC_DEMO: discover service complete conn_id 0
I (8208) GATTC_DEMO: SEARCH RES: conn_id = 0 is primary service 1
I (8208) GATTC_DEMO: start handle 20 end handle 25 current handle value 20
I (8218) GATTC_DEMO: service found
I (8218) GATTC_DEMO: UUID16: fff0
I (8228) GATTC_DEMO: Get service information from remote device
I (8238) GATTC_DEMO: ESP_GATTC_SEARCH_CMPL_EVT
I (8238) GATTC_DEMO: ESP_GATTC_CFG_MTU_EVT, Status 0, MTU 248, conn_id 0
I (8248) GATTC_DEMO: ESP_GATTC_REG_FOR_NOTIFY_EVT
E (8248) GATTC_DEMO: decsr not found
I (8298) GATTC_DEMO: write char success

若单独注册NOTIFY服务，则报错：

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I (5918) GATTC_DEMO: connect to the remote device.
I (5938) GATTC_DEMO: stop scan successfully
I (6998) GATTC_DEMO: ESP_GATTC_CONNECT_EVT conn_id 0, if 3
I (6998) GATTC_DEMO: REMOTE BDA:
I (6998) GATTC_DEMO: 25 79 62 57 60 74
I (7008) GATTC_DEMO: open success
I (7628) GATTC_DEMO: discover service complete conn_id 0
I (7638) GATTC_DEMO: SEARCH RES: conn_id = 0 is primary service 1
I (7638) GATTC_DEMO: start handle 20 end handle 25 current handle value 20
I (7638) GATTC_DEMO: service found
I (7648) GATTC_DEMO: UUID16: fff0
I (7648) GATTC_DEMO: Get service information from remote device
I (7658) GATTC_DEMO: ESP_GATTC_SEARCH_CMPL_EVT
I (7668) GATTC_DEMO: ESP_GATTC_CFG_MTU_EVT, Status 0, MTU 248, conn_id 0
I (7668) GATTC_DEMO: ESP_GATTC_REG_FOR_NOTIFY_EVT
E (7708) BT_L2CAP: slave connection parameters update failed, the parameters are out of range
I (7708) GATTC_DEMO: write descr success

代码基于gatt_client例程，与类似设备（ble 4.0版本，服务和特征UUID完全相同）连接正常运行，见附件。请问是什么原因？