As a tech guy I am very used to dealing with issues of various types relating to my software, hardware and services.
Many times a good search engine is my friend as I researched if others have experienced similar issues with the same service.
Recently I had been having intermittent problems with the connectivity to our Office 365 hosted Exchange accounts. It was completely random when it would happened and a variety of solutions I found online appeared to fix things but they always ended up being temporary remedies.
I know it was not an Outlook client issue because it was happening on all of our devices connected to the home network and those connections were both wireless and wired. I rebooted routers, switches, etc. in the hopes of restoring proper connectivity but everything continued to be intermittent.
Two other things that helped me narrow it down to being related to my COMCAST/Xfinity internet connection was that those Office 365 accounts always connected on our cell phones with AT&T. I was also able to consistently connect to Office 365 using my travel router and data modem/stick.
With those additional pieces of information I was able to refine my search and track down a solution that allowed me to restore full connectivity on our home network. Once that change was made our hosted exchange account connections have been rock solid.
What I did was disable the IPv6 option on my COMCAST/Xfinity modem/wireless router setup. Once I rebooted the device the connections to our Office 365 Hosted Exchange accounts have not failed.
Let me add that this step does not make sense in some ways because I have had this new router/modem combo for a few months and the connectivity issues began in the last few weeks and IPv6 was enabled on the device since I installed it.
Bottom line is that I am happy to have complete connectivity back again however, I hope the issue with IPv6 being selected is resolved so that functionality can be on by default once again.