Trying to validate NXDOAMIN error


This is for the IIS on a W12 R2 server with a skype for business server.

Im a bit lost here, im getting this error, but i doble check on the Router 53 DNS txt records and are ok

The error is:

Validation of the required challenges did not complete succesfully. DNS problem: NXDOMAIN looking up TXT for

the only odd thing i could notice its that the value for the domain root never change but the one for the www change every time i relaunch the petition.

any advice?

Hi, normally NXDOMAIN just means that it can’t find the TXT record at all (the other one has probably been found OK and therefore doesn’t need to validate again).

You can try diagnosing the problem using otherwise please send an email to with the full details and your log file to support at

Maybe I’m not giving you enough credit for masking your error messages, but isn’t “contoso” a fake example company that Microsoft uses?