I am having the same problem. My emails won't send from my Outlook Account although I receive them as usual. This started Wednesday morning, May 16th. I've been on the phone countless hours with both Microsoft and Comcast. My error messages say Sending' reported error (0x800CCC67):' The server responded: 421 resomta-ch2-03v.sys.comcast.net (My IP address) is not permitted to send messages. Please contact support if you think this is in error.
I do have internet service with Frontier but have been paying Comcast separately for the continued use of my comcast email address.
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