So I was able to migrated fine from 2003 to 2010.
Only ran into a couple of issues
1. Outbound mail is coming out of .226 instead of .227. It needs to be .227 since .226 is blacklisted.
This is probably why I'm getting this messages:
BL2FFO11FD022.mail.protection.outlook.com gave this error:
Service unavailable; Client host [x.1x.x.226] blocked using Blocklist 1; To request removal from this list please forward this message to firstname.lastname@example.org
Not sure what's going on here, routing group was deleted from 2003 to 2010
Could this also be related to outbound messages not going out and stuck in the queue?
550 connection refused.