Outlook displays banner that says: Check your connection Open a browser to sign into ______.com and receive new emails

I had this same issue after my network gave out and reconnected.
However for me it was solved after I noticed that Outlook displayed the text "all folders are up to date" "need password" on the right bottom in the grey area.
After clicking it, Outlook connected (without putting in my password or a code mind you) and the banner was gone.

I suspect the link in the banner is for authentication purposes. However it doesn't seem to properly load besides a popup asking permission for Outlook to configure server settings.

So if you have this problem I suggest checking if Outlook is asking you for the password in the right hand bottom corner.

Resolved but was like "Great another Monday morning issue with windows!"... It would appear that after my last auto-update at shutdown on Friday my tower's wi-fi connection became enabled. I turned off my wi-fi adapter in the settings again and closed the banner. Hasn't popped back up yet. Hope that helps.

I am also having this issue. Has anyone been able to resolve it?

I just started having this same issue too. I'm a home user, on wired LAN, using Microsoft 365 Family subscription. What I also notice is after the banner shows up in Outlook, within a few minutes my browser launches all on its own and goes to an MSN page. When I close the browser, this happens again about every 3-5 minutes or so.

I had this same issue come up over the past few days. Using a home computer, home network, Windows 10 PC,  Outlook 2016. I disabled and re-enabled my Ethernet connection and that seems to have fixed it. I did note that when I first looked at "Ethernet status", it showed IPv6 Connectivity as "No Internet". IPv4 was good. After I disabled/re-enabled the Ethernet adapter, both IPv4 and IPv6 show "Internet".

Control Panel --> Network and Sharing Center

-click "Ethernet" link on right side of screen near "Access type"

-from Ethernet Status box that pops up, click "disable"

To re-enable, I right-clicked the network icon on the lower right corner of the desktop, ran the network troubleshooter, and it re-enabled the adapter. I'll bet there are some other ways to do this too-this is just the one I found first.