Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
First. Leaving an Access database open when putting your computer to sleep is a bad idea in any event.
From the description you posted, it sounds like you have an Access Front End connected to a Back End on a network, or to a remotely hosted database. That connection was lost when you left it open overnight. Reopening Access re-established the connection, so all is now functioning as normal.
So, the question is more relevant to how your database is deployed than whether your computer is connected to the web to use Access 365.
That said, it is true that Microsoft 365 is reliant on a web connection for things like updates.
More to the point, though, is understanding how this database is designed and deployed.