I also got this from outlook.office365.com when I installed a replacement hitron modem from rogers this morning. See this other post: https://communityforums.rogers.com/t5/Internet/Hitron-Router-Man-in-the-Middle-Attack/m-p/434462/highlight/false#M...
Wow I just ran into this same issue. I installed a replacement Hitron modem from Rogers just this morning and afterwords I received a certificate warning from outlook.office365.com from the same CA (CableLabs Inc. Cable Modem Root Certificate Author...
