Cannot update Avira

This actually started some months ago on both my PC's at pretty much the same time. I use Avira as AV. For some reason though it just wouldn't update anymore. Normal the updater gets to about 250kb, waits half a minute then does another 250kb, waits half a minute... etc. Somewhere between 1 and 1,5MB into the update it just stops and a few minutes later it shuts itself off. About two months...