Successfully Authenticates, but gets Oops... error (Only occurs when accessing M365 in Firefox)

I have a user who constantly gets the “Oops… Looks like something went wrong.” error page after successfully authenticating to access their Microsoft 365 web apps in Firefox on one specific Windows10 device. (Error page prompts after authentication, which shows successful)

However, they can authenticate and access their M365 apps without any issue from Chromium based web browsers on this same device.

I’m a relatively new Duo administrator for my organization, so I was just posting to see if any has seen a similar issue (sorry if I sound daft). I’ve already tried the basic Win10 desktop troubleshooting techniques, e.g. cleared cookies & cached data, completely removed Firefox and its app data followed by a clean install of the app, and even had the user replicate the same issue in another user profile on the device.

Hi @austinanders, welcome to the Duo Community and the world of Duo administration! First, you don’t sound daft, and there’s no need to apologize - we are all just learning here! Many of our members are beginner or newer Duo admins like yourself.

You’re not the only one experiencing this issue either. I see from the URL in the screenshot you shared that you are using Azure auth. There was recently an incident with Azure Conditional Access Authentication failures that caused a similar error to occur, but that has since been resolved.

I also found this knowledge article that seems like it might help here. Is it possible this user is using Quick Assist, and are you using Duo Access Gateway or Azure’s Conditional Access (CA) application? Check out how to resolve an ‘Oops’ error while logging in to Quick Assist behind Duo-protected Office 365 for info.

Ultimately, you might be better off contacting Duo Support for this. They can do official troubleshooting and tell you exactly what’s going on here!