for the last several years, I have used smtp-server.cfl.rr.com as my outbound server for all my email accounts within outlook and thunderbird. This morning, I received a message "An error occurred while sending mail. The mail server responded: 4.1.8 - Domain of sender address firstname.lastname@example.org does not accept inbound mail [R0307001]. Please verify that your email address is correct in your Mail preferences and try again."
Has something change on rr enforcement side in the last 24 hours?
I changed the outbound to my hosting email servers and everything is delivered.
I am just wondering about the change.... and why after nearly 10 years is this in effect