Sql-connection timeout error for a particular period of time

See more:

SQL

SQL-I am getting following error for particular time period-like 6 am to 6:30 am-
The code is a part of a Service which is called by some job-Here one Store Proc is being called and connection to SQL DB getting failed at around 6:30 (for 10 mins)

System.NullReferenceException: Object reference not set to an instance of an object.     at System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject)     at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection)     at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)     at System.Data.SqlClient.SqlConnection.Open()     at Hallmark.ProducerPortal.WebServices.VantageBrokerService.SearchAgents(SearchAgentsRequest searchCriteria) in d:\TFS_RETAIL_Builds\31\VUI-RPP\PPWebServices_R22\src\WebServices\VantageBrokerService.asmx.cs:line 102  

After 6;30, the same code execute without any exception (though with less data)

What I have tried:

I have analyzed the DB, what are the other jobs, SQL script are running in the DB server which may consume much memory of the DB.I have stopped 2 jobs(which was consuming high CPU) which was running around 6:30 am . Still not working.