I already answered your question in the off-topic thread you opened in the Skyrim section, but I'll add it here as well for others to see.
It is indeed a 'known problem' that some people don't know how the latest NMM version functions now, because they missed reading the Site News about it or whatever.
The tool is very well working though for 'almost' all of the site's users so far. Only a handful of people in comparison are still having trouble with it, and we're trying to figure out why exactly that is for each one individually.
The error message already told you you're still offline with your NMM, not connected to the servers yet, but you never mentioned anything about you logging in with it so far.
There's a little red buddy icon in the bottom bar signaling you're currently offline. If you click this, you will either be asked for your login credentials, with the option to store them for next login, or having stored them before will automatically log you in.
The buddy will then turn green, signaling you're now online and connected to the Nexus servers, and next to it will appear a little box with a download meter, for when you have any downloads running to meter your average speed or such.
All features requiring access to the Nexus servers will need you to be logged in. I tested some situations myself and so far not 'all' of them will immediately trigger the login popup like they should be. So always make sure your NMM is online and connected to the servers before attempting to use any of these.
I haven't found any 'automatic' scanning and update notification so far though. These things will likely only take place when you connect and then click the green curved arrow icon on the left sidebar.
All automatic checking I found so far is the check in the settings for updates to the client itself, nothing for mods that I could find.
The NMM is still in beta testing stage and you voluntarily agreed to join the Open Beta. Nothing is forcing you to use the client and likely never will be. If it is not to your liking or expectations, simply don't use it. There are numerous other ways to download and/or manage your mods and always will be. Or you can just wait for a finished release version to come out and try again then. Most issues people are currently still having should then really be fixed.
And you being a Life Time Premium Member or not has nothing to do with anything in this regard. It's none of the perks you're entitled to as thanks for your donation to the site's upkeep. I would've given, and will give, the same reply to everybody else asking for help.