EMails from my comcast.net address are not being received by addressees

Since about March 23, 2020, emails I send from my comcast.net accopunt are not being received by the addressees.  I've tried both sending themfrom Outlook and the Comcast email service with the same result.  The messages show as sent in my Sent box, but the recipients never get them and I do not get a "not sent" notification.  I tried sendign my self an email and the email ends up in my junk/spam folder, even though I've repeatedly indicated emails from me are not junk/spam.  How can this be corrected?