DB connection issue from IIS 7.0

Hi,

I'm able to connect to a database "A" from my server with integrated mode, but if I change the connection string to server "B" , I'm getting the following error. Firewall is open for DB A & B from my serever and able to connect from any vbs file or ODBC. Please help me out.

Error in Datasource: <"B"> Database : <"DBName">, Error:    at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
  at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)
  at System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, SqlConnection owningObject)
  at System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, Int64 timerExpire, SqlConnection owningObject)
  at System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(String host, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, Int64 timerStart)
  at System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(SqlConnection owningObject, SqlConnectionString connectionOptions, String newPassword, Boolean redirectedUserInstance)
  at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, String newPassword, SqlConnection owningObject, Boolean redirectedUserInstance)
  at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection)
  at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options)
  at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject)
  at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject)
  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()