No flowing emails from 2010 to 2003.

We are on exchange migration  2003 to 2010, all emails from both servers to/from  outside works , same with emails from Exchange 2003 to 2010. The issue is sent emails from 2010 to 2003.

We have Spam Mail Server for outbound and inbound external emails.

The following steps ware done:
1- Connectors bidirectional:
 New-RoutingGroupConnector -Name "Interop Exchange 2003" -SourceTransportServers "exchange2003.localdomain.local" -TargetTransportServers "exchange2010.localdomain.local" -Cost 1 -Bidirectional $true -PublicFolderReferralsEnabled $true

2- Check telnet from both servers.

Thanks