Delivery failure User not listed in Domino Directory

I have installed 3 new version 8 servers in my domain and migrated all users to the new enviroment from our ‘old’ 6.5 server. I have created new users on the new server without any issues, but since a while a couple of the new users are giving me some errors.They can be emailed personally just fine, within our domain and from the internet, they can email to everyone, also in and out of the company.

Now when I add them to a group or sent an email to them with another user in cc, they give me a delivery failure.

the error I got is User XXX/company (XXX/Company@company.nl) not listed in Domino Directory

What the weird part is, is that the email addresses normally are XXX/company/NL (XXX/Company/NL@company.nl) so for some reason the system changes the addresses.

any ideas where I can find the solution for this?

Subject: I had this same problem

Definitely look at domain in the person document.Mail system: Notes

Domain: (if blank or not)

If the Domain is filled in, it adds that other @domain. If it is blank, or the same as your default domain, it should skip it.

Frank