Gray Cloud

I'm getting this error on one of my CAS 2007 / Windows 2008, i need any
explanation of it:

The 'legacyExchangeDn' attribute for Exchange server nsd-cas-01 does not
match the parent administrative group. This will cause reliability problems.
Current 'legacyExchangeDn' value: /O=EXNSD/OU=EXCHANGE ADMINISTRATIVE GROUP
(FYDIBOHF23SPDLT)/CN=CONFIGURATION/CN=SERVERS/CN=NSD-CAS-01.

Thanks a lot.

Andrea