Even without installing a newer version of Avast, you could check yourself your settings:

Avast main GUI → Settings → Updates.

Do you have “engine and database” updates set to “automatic”?

In that same section, could you try setting the “Proxy Settings” to “no proxy”?

Then save the settings, REBOOT, connect to the Internet, and wait several minutes so to let Avast update all the database (it could be 200KB, or it could get to all the database, about 30MB ).

After waiting several minutes, check “Main GUI → Maintenance → Update” to confirm if the database was indeed updated.