Do you recognize this alert? 

SMS_SERVER - SMS 2003 Perf Threshold: SMS SQL Connections > 500 over 2 hours.
SQLServer:General Statistics: User Connections: value = 300,5. The average over last 2 samples is 300.5. 

The cause might be that the MOM agent has a large number of connection from sqldmo_%/sqldmo_(number) to the database. The agent not always disconnect. Try to restart you mom agent, you can do that by the following command 

net stop mom
net start mom