Reserved group names
Some group names are reserved and can't be used as the names of groups you create in Google Groups (groups.google.com). However, you can use reserved names as group names when you create groups in the Admin console.
The following group names are reserved:
About groups named abuse and postmaster
The names abuse and postmaster are handled differently than other reserved names. If you create groups with these names in the Admin console, you might see "Settings weren't saved because an error occurred," but the group will still be created. This error appears because the settings for the abuse and postmaster groups can't be changed. You can, however, subscribe to these group addresses and receive all email sent to them.