This old issue is only reported by CrossOver 21 and older. See the current Missing or broken libnss_mdns.so.2 library page for more details.
On CrossOver 17 and greater, the simplest solution to fix this issue is to run:
/path/to/cxoffice/bin/cxfix missinglibnss_mdns missinglibnss_mdns.amd64See the current Missing or broken libnss_mdns.so.2 library page for more details on how to install this library.