Cause of 'Temporary Failure' message

I received this message when replying to an email I received from a known person, whose email I have x'd out.

This is an automatically generated Delivery Status Notification.     

 

Delivery to the following recipients was aborted after 49.4 hour(s):

 

  * [Edited: "Personal Information"]

 

Reason: Temporary Failure

The attached details file to the error email includes this;

Reporting-MTA: dns; resqmta-h1p-028588.sys.comcast.net [96.102.179.242]
Received-From-MTA: dns; resomta-h1p-027908.sys.comcast.net [96.102.179.197]
Arrival-Date: Sun, 28 Jan 2024 15:12:32 +0000

Final-recipient: rfc822; [Edited: "Personal Information"]
Diagnostic-Code: smtp; Connection error
Last-attempt-Date: Tue, 30 Jan 2024 16:35:59 +0000

This message has been received several times, the last stating my email was aborted after 47.4 hours, but they continue.

Question 1: What causes this?

Question 2: How can it be cancelled?