Configuring FTP Monitor for Passive FTP VIP at F5

Hello,

There is a FTP VIP configured at F5. This is a Passive FTP VIP. F5 VIP is listening on 21 port and backend servers is listening on 7021 port. And F5 is doing Automap.

This F5 VIP is working but no FTP Monitor was set and when I am trying to set a FTP Monitor Pool is going Down ( Red ).

To provide a visual brief I attached couple of screenshots. Question is where could be the problem I am doing while setting the FTP Monitor ?

When you will see my Pool Image Availability section says ( Unknown .... ) at that time no FTP Monitor was called. But when I set the FTP Monitor it goes RED. In the Member section of Pool it also says the same. Also attached the Monitor Config Image.