Apple device email clients not working with comcast.net accounts

I've noticed over the past several days or even weeks that I could no longer send emails from either of my comcast.net accounts using Apple Mail on Mac. I've also had sporadic connection issues on iPhones and iPads. Today, every single Apple device I own is unable to connect to either of my comcast.net email accounts. I've deleted account data on Mac and ios devices and tried to set up accounts from scratch and none worked. I've tried connecting to comcast.net accounts on the Mac with 3rd party clients like Spark and Canary and neither worked. I got the blacklisted IP error on one iPhone and IMAP password prompt on others which failed to connect even with correct password. The Apple Mail client on Mac prompts for passwords or now fails to connect at all, as if Comcast email service didn't exist. I have verified that both account settings are checked to allow 3rd party clients and have even changed passwords on both to no avail. It's obvious I can still use the web based email, but that is unacceptable in even the short term. I only became aware today that Comcast was in the process of offloading all accounts to Yahoo. I do not recall ever receiving email from Comcast/Xfinity to that effect and do not see any way to force the switch manually at this time. It seems that you can only do that when you receive the email to make the switch. There are several recent posts mentioning all of these issues, but none as detailed as mine. Comcast needs to offer a solution or allow immediate switch to Yahoo for anyone having this problem. I have no issues with my existing Yahoo email account on Apple device clients.