[Users] monitor ser

Hi, I'd like to use monit to monitor ser. Sometime ser has the pid file, but stops responding to any request. I want to periodically send an OPTIONS message to the udp port 5060 and expects the answer back. However can't make it work with monit. The config is something like this, check process program with pidfile /var/run/ser.pid start program = "/etc/init.d/rc.serstart" stop program = "/etc/init.d/rc.serstop" if failed port 5060 type udp send "OPTIONS sip:test@........" expect "SIP/2.0 200 OK" with timeout 2 seconds then alert I can see the reply with ngrep. But monit still reports "connection failed". Any suggestion? Thanks, Richard