Comcast Users

Please note that Comcast is rejecting all my emails with the following error!!!!

(reason: 554 IMTA19.emeryville.ca.mail.comcast.net comcast 211.29.132.8 Comcast BL004 Blo)

----- Transcript of session follows -----
554 5.0.0 Service unavailable

I am therefore unable to reply to any emails originating with Comcast. This problem has existed for some time with no sign of a solution

The Webmaster

Note. Other error messages have also occurred in the past

Update: I'm now getting a slightly different message with no indication of the error.