HTTP monitor_ Redundant pair member LTM Marks Resources as unavailable

The monitor configuration is this:

ltm monitor http /Common/Exchange_2010_Prod.app/Exchange_2010_Prod_ad_http_monitor { app-service /Common/Exchange_2010_Prod.app/Exchange_2010_Prod defaults-from /Common/http description none destination : interval 10 manual-resume disabled partition Common password none recv none recv-disable none reverse disabled send "GET / HTTP/1.1\r\nHost: mail.cajadeande.fi.cr\r\nConnection: Close\r\n\r\n" time-until-up 0 timeout 31 transparent disabled up-interval 0 username none }

But we change for a default HTTP monitor and the problem persist.

On the other hand, the Pasive box works perfect. We executed a force to standby on the active box and it failed over correctly to the other box and all of the services started to work normally. Then we discard network problems.