can't download updates in 4G.

The system tries to auto-update, then gives me an error message. When I try to update manually I get the same result. By trial and error I found that by resetting my phone card to 3G, then manually updating, does work.

Since I changed from 3G to 4G my AVAST! won’t auto update. It tries to auto update and gives me a error message.
To get updates I must Shut down my SPRINT Smartview, change to 3G, boot AVAST and manually update, then change back to 4G.

Is there any way I can get auto update on 4G?