Updated Post 9/10/18:

In working with the original reporters, the issue was isolated to being connected to “Denison-Guest” instead of “eduroam”. Once the individuals selected “eduroam”, the problem resolved. Please note that a connection to Denison-Guest requires re-registration every 48 hours to continue Internet access so members of the Denison community should NOT connect to “Denison-Guest” as it will not yield a reliable long-term connection. If you have any difficulty connecting to eduroam, please contact the ITS Help Desk at 740-587-6395 or helpdesk@denison.edu.

Original Post 8/31/18:

ITS has received 3 reports in the last 18 hours of an “Invalid Certificate” error when trying to approve logins through Duo. All were on iPhones.

If you experience that error, the immediate workaround is to use a passcode:

• On the Duo approval screen on your computer, select the “Call Me” or “Enter a Passcode” option instead of “Send Me a Push”.
• If you choose “Enter a Passcode”, click the “Text me new codes” button in the blue bar that appears to receive passcodes via an SMS message. (The passcode generated by the Duo Mobile app on your phone may not work.)

A Duo support article indicates that is likely a network-related error. To troubleshoot:

• Please check your iPhone to see if you have WiFi turned on. If so, confirm that it is connected to “eduroam” and NOT “Denison-Guest”. If you are not already connected to eduroam, please connect to eduroam using your Denison email address as your username and your Denison password.
• If WiFi is on and connected to eduroam and you are able to get to web pages in a browser on your phone, please try turning WiFi off and see if the problem persists.

Please report the issue and your findings from the above troubleshooting steps to the ITS Help Desk at helpdesk@denison.edu.