Updating repository returns NODATA

[yusuphtunday]

Help please, am trying to update my source list to install GNOME, but updating seems impossible
Here what I get when updating

E:GPG error: http://viewizard.com debian/ InRelease: Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?)

[deadflowr]

It is unclear what you are running, system-wise

Please post what system you are running, at least.
or else even the sources.list file...