UPDATE: Sonicwall is aware of the issue with their content filtering service (CFS) blocking msftncsi.com. They are working to fix the issue this week and recommend implementing a allow URI list for www.msftncsi.com and msftncsi.com.
Microsoft Windows 10 and 7 perform periodic checks to see if it is properly connected to the Internet. The check essentially does a quick ping at http://www.msftncsi.com/ncsi.txt and evaluates whether the result is “Microsoft NCSI”. If the check fails, then Windows displays a yellow triangle on the Ethernet or WiFi adapter indicating that the system is connected to a network but does not have Internet connectivity.
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Unfortunately Microsoft Office 365 desktop apps use the aforementioned network adapter status. If it is in error due to a failed msftncsi.com check, it will prevent users from completing modern authentication. The dialog will simply state: “We are unable to connect right now. Please check your network connection and try again later.”
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Sonicwall is aware of the issue and is working to resolve it but recommends users to create an allow URI object for www.msftncsi.com and msftncsi.com. Here’s how:
- Navigate to Manage->Objects->Content Filter Objects->URI List Objects.
- Create a new list named Allowed List or whatever verbiage you prefer. Then add both www.msftncsi.com and msftncsi.com.
- Navigate to Manage->Objects->Content Filter Objects->CFS Profile Objects. Find your active policy profile and edit it. Ensure that your Allowed List is selected in the appropriate area.
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