使用 2900 系列路由器，我遇到以下问题：

hostname#show flow monitor
  Flow Monitor TESTFLOW:
  Description:       User defined
  Flow Record:       TESTFLOW
  Flow Exporter:     TESTFLOW (inactive)
  Cache:
    Type:              normal
    Status:            allocated
    Size:              4096 entries / 10404496 bytes
    Inactive Timeout:  15 secs
    Active Timeout:    1800 secs
    Update Timeout:    1800 secs


hostname#show flow exporter
Flow Exporter TESTFLOW:
  Description:              User defined
  Export protocol:          NetFlow Version 9
  Transport Configuration:
    Destination IP address: 192.168.x.x
    Source IP address:      172.16.x.x
    Source Interface:       GigabitEthernet0/0
    Transport Protocol:     UDP
    Destination Port:       3008
    Source Port:            61496
    DSCP:                   0x0
    TTL:                    255
    Output Features:        Used
  Options Configuration:
    exporter-stats (timeout 100 seconds)

为什么会Flow Exporter: TESTFLOW (inactive)出现？

如何将其设置为活动？