no pool member available

Hello,

we have an app that point at 2 pools, somehow we lost access to the app, on a BIGIP behind the WAF we are getting the error no pool member available, by default, the pool health monitor was set to TCP

however even after setting up the receive string, the status of the pool changed to offline 

< HTTP/1.1 302 OK
< Cache-Control: private
< Content-Type: text/html

Regards.