AD error repeats

Newer versions have more verbose error message:
```
netads = await run(cmd, check=False)
if netads.returncode != 0:
err_msg = netads.stderr.decode().strip()
if err_msg == "Didn't find the ldap server!":
raise CallError(
'Failed to discover Active Directory Domain Controller '
'for domain. This may indicate a DNS misconfiguration.',
errno.ENOENT
)

raise CallError(netads.stderr.decode())
```

Do you have DNS properly configured? This is usually a DNS error.