Sometimes activating the DNS zone of a domain can give the error “DNS zone of a domain alias cannot be edited because the domain alias is turned off”. To correct this, open up command prompt in Remote Desktop and type the command
cd %plesk_bin%
Next, enter the command below (in one line) replacing domain.com with the affected domain
dbclient.exe --direct-sql --sql="update dns_zone set status=0 where name='domain.com';
You can then switch off and on the DNS and it should resolving fine.