This time I got an email from Yahoo with an "explanation" why they did not accept the message. I looked at the links. The first one has to do with simple guidelines and the second link from Yahoo does not work.
"We are unable to deliver the message from <[my correct email address]>
to <PanoToolsNG@yahoogroups.com>.
Your email was not delivered due to a suspected guidelines violation. Please visit
http://groups.yahoo.com/local/guidelines.htmlIf you feel you've gotten this email in error please visit the following link for more information
http://help.yahoo.com/kb/index?locale=en_US&page=content&y=PROD_ACCT&id=SLN3263