The exclamation mark is a problem/notice that needs attention, it is a lower priority than if it were a Red X (serious problem). If you disable a shield or set updates to manual for instance you would have the exclamation mark to draw attention to it. Whilst the exclamation mark is present, you won't see an animation of the avast icon as this avast! tray icon with the exclamation mark replaces the animated one.
If you see the exclamation mark over the avast icon, you need to open the avastUI, Summary screen and identify what the exclamation mark is for, e.g. what shield is stopped, etc.
An update from the control panel may succeed where the normal one would fail as I believe that has a higher privilege level.
####
I would suggest that you check the avastUI, Settings, Updates, scroll down to the Update Parameters and set it to the connection method you use, 'My computer is permanently connected to the internet.'
Now scroll down the the Proxy Settings and expand that option, see attached image, click to expand. Ensure that you have it set to 'Direct connection (no proxy)' if you don't actually use a proxy to connect to the internet (usually not the case). The default proxy setting is usually 'Auto detect (use Internet Explorer settings' at times there can be a problem actually getting the proxy information from IE and that could impact on the auto update function.