I have a Samsung tablet running Android 5.0.2. Since roughly the new year it has been reporting a system update available. It took me a few days to clear off the 270MB its asking for, but I've done so. However, when I try to update it through About device -> Software Updates, it reports failure due to my network not having Internet access.
I'm typing this on the tablet right now, and I assure you I'm not using elfin magic to move the bits to the SE server. Clearly its Internet access is just fine.
Has anyone else seen this before and / or know what's going on here?