can't send comcast.net emails from iPhone or Outlook

I am having problems with sending my comcast.net emails.  My wife and I each have a comcast.net email, and in the last month or so we can receive but not send.  This is true for my wife on both her iPhone using the native Apple iPhone mail app, and on her Windows-11 pc using Microsoft 365 Classic Outlook.  Likewise for me on my iPhone and pc.  However, when I go to my web browser on my pc and open the comcast.net/xfinity email program there, It works!  I see all my folder structure, etc.  Why not in Outlook or on the iPhones?  Ans especially with two independent email accounts?  Spent hours trying to talk with Comcast support, with no success.  Today I looked here in these support forum comments, and see some people have had similar problems and found out their sending problems were due to Comcast blocking their accounts, and the Support Tech was able to unblock it to fix it.   Hope Comcast Support can help me?