I spent an hour with support and they couldn't get this working for me. My email was working on all my devices and my other comcast accounts were also working. This one comcast account was not syncing only on my pc with office 365. No matter what I tried, Outlook kept saying "Something went wrong, we could not save your settings."
If you go into your control panel on Windows (I have version 10) and change the view so you see icons instead of categories, you will see an outlook configuration app. Go in there, highlight the account and edit the settings. You might have to drill down to see the advanced options for SMTP. This is great because the "test" button will tell you what part is failing. Took me 60 seconds and I fixed everything.
For whatever reason, this outlook configuration actually works, even if the settings are the same. I think there's some kind of coruption going on behind the scenes. Wanted to share this because it was driving me nuts and comcast support couldn't assist me. I'm an IT professional with 30 years experience, so I don't give up easily.