My Centralized Mail server is behind NAT and has internal IP address.
When I am trying to reload the Plesk server in CMail, the action executed with the error:
<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
<errtext>Domain adding was failed. Error: Unable to get ip id by address from db</errtext>
This problem occurs because of Expand knows only about external CMail server IP which was used for CMail registration in Expand. But that IP does not exists on CMail because it is staying behind NAT. So, Expand tries to create domains on CMail with non existing IP and the error listed above occurs.
This problem can be solved by using internal IP for domains creation on CMail server. This IP can be set on "Centralized Mail > MAIL_SERVER_NAME > Preferences" page in Expand CP. After that new domains on Cmail will be created with this internal IP. To change IP for already existing domains use "Centralized Mail > SERVER > Repair" button.