Mac Mail won't allow me to add a Comcast account
Up until a few days ago, my Comcast account was working fine on my Mac. My Mac is running El Capitan 10.11.6. A couple of days before I started seeing email issues, I also had problems with web access in general, and through the diagnostics determined the DNS settings were wrong. Maybe this was due to something at Comcast, maybe not, but it seems suspicious given I'm now having issues with email.
Starting a few days ago I started seeing intermittent problems where I'd get the little triangle with an exclamation point in it in the Mail tool. Sometimes it would ask me to re-enter my password, and that generally worked. This morning I was still seeing issues so decided to delete my Comcast account from the Mail app, and then try to add it back in. And that's where I'm stuck. When I put in the email address and password (which I'm 100% certain I'm entering correctly), I get a message that says "Unable to verify account name or password". There is no option at this stage to enter any account settings other than IMAP vs POP (I'm using IMAP) and Incoming and Outgoing servers, which are set to imap.comcast.net and smtp.comcast.net.
Some additional notes... I'm able to access the Comcast web email without issue, and I can also access email from both my iPhone and my Mac laptop (also using Mail). It may be worth noting that my laptop is setup to have this account as POP and not IMAP, but it's been set that way for years with no issues.
Any thoughts as to what's going on here?