Currency is traded using product type as NRML and not CNC for overnight positions.. Margin requirement is update on the SPAN file or you can also use the SPAN calculator to check it out..
We've checked this out at our end and it seems to us that the issue has to do with your location. Are you located somewhere outside India? Or are you working behind a proxy?
If it's none of the above, it could have been a temporary issue with NOW at your end due to a connectivity issue with the Internet.
If the problem persists, please call us on 080-40402020 for assistance.
Hari