Office365 parent and sub domains

[NETKILLER]

I am in the middle of setting up office365 for student access only. At the moment I have added the parent and the sub domain and have created some test users on the sub domain and they work fine with each other and other @DomAin accounts. However when I email the parent domain from an office365 sub domain account, it does not work.

 

Error message

Your message to “[email protected]” couldn't be delivered.

parentusername wasn't found at parentdomain.org

subdomainusername Office 365 parentusername

 

Unknown TO address

How to Fix It

The address may be misspelled or may not exist. Try the following:

• Retype the email address then resend the message.

• Clear the recipient nickname cache in Outlook or Outlook Web App by following the steps in this article: NDR Response Code 5.1.10 in Exchange Online and Office 365.

• Contact the recipient (by phone or instant messaging, for example) to check that the address is correct.

• The recipient may have set up mail forwarding to an incorrect address. Ask them to check that any forwarding they've set up is working correctly.

If the problem continues, forward this message to your email admin.

 

I don’t want to set up office hybrid at the moment, so my question is, is there a way to setup some kind of mail flow or redirect for all “[email protected]” to our existing external mail filtering system?

[NETKILLER]

issue resolved will try and put up how when i can