Error message in ESB Console and nothing appears in Tracking tab

Sometimes we face very strange issue in ESB console. Nothing appears in the tracking tab of the ESB Console and the error message comes as:

Unable to build the instance relationship, as the required metadata is not available.

First check the size of the log files. sometimes if the log size is very large then the server doesnt behave as expected.
go to  <oracleHome>/opmn/logs/
type ls -lh to find the size of the log files.
If the size of the log file is very big then we need to empty the file.
first stop the server (go to /opmn/bin/  then type ./opmnctl shutdown)
take the backup of the log file.
cp SOA_GROUP~oc4j_soa~SOA_GROUP~1.log backup_SOA_GROUP~oc4j_soa~SOA_GROUP~1.log
empty the log file.
cp /dev/null SOA_GROUP~oc4j_soa~SOA_GROUP~1.log

Then start the server (go to /opmn/bin/  then type ./opmnctl startall)

This is how my issue got resolved. Not sure if reducing the size realy helped or bouncing the server.
If anyone has a bettor solution then please share.