Issue with teams

[rvalencia87]

Hello good evening.

In my job we have different SSID, with different group policy, well today I received the complain from one site because the app and the site of Microsoft teams didn't work, they opened their app and the app doesn't show the textbox to put the password, and the received the message that "the site is blocked", additionally the icon of the wireless network shows like the computer doesn't have Internet connection, and if you displayed the icon to see the status of the network, this show the message "click to open a browser and sign in to the network" and the icon was the world which shows when yo don't have Internet, but the fact is that the network doesn´t have a splash page. 

With my boss and another coworker we look about the address for microsoft teams, to allow them in the group policy, so we googled "fqdn wildcard microsoft office 365" and the search shows this address: *microsoft.com
*microsoftonline.com
*office.com
*skype.com

After we added this address to the allow list of the policy group, the App and the site of Teams was available for the user, and the message "click to open a browser and sign in to the network", and the icon of the network was turn to normal again. 

But I don't know what could happen, why the network icon, and the message to "click to open a browser and sign in to the network" appears, no one of our team had made changes in the network. 

Does anyone has experienced a similar problem???

[Nicholas944Saul · Accepted solution]

Hello!

What you saw is essentially Windows (and other OSes) treating the situation as if the network required captive portal authentication. When critical Microsoft service endpoints (like *.microsoft.com, *.microsoftonline.com, *.office.com, *.skype.com) are blocked, the system can’t reach the URLs it uses to verify internet connectivity. As a result, the network icon flips to the “no internet” globe and shows the “click to open a browser and sign in” message—even though your SSID doesn’t actually have a splash page.
By allowing those FQDNs in your group policy, you restored Teams’ ability to reach its authentication endpoints, and the OS could confirm internet access again. This behavior isn’t unusual: if the OS can’t reach its designated test URLs (often Microsoft or other vendor endpoints), it assumes the network is captive. So the root cause was simply that the policy was blocking required Microsoft domains, which made the system misinterpret the network state.