YAHOO Mail Won"t Stop Sending

I just had a new POP3 mail account set up and forwarded some mail from my
Yahoo account to the new POP3 account. One email included several
attachments that resulted in that message exceeding the allowable size for
the new account. I received a message from Yahoo that the message couldn't
be delivered. Ever since then, however, a warning message has been
delivered to my POP3 account about every 30 minutes indicating that I tried
to send a message from my Yahoo account that was over the size limit. I
have sent several messages from my Yahoo account to the POP3 account since
the problem message and they've all went through. Just trying to figure out
how to stop the constant stream of warning messages. Any ideas? From the
message it sounds like Yahoo is continuing to try sending the message even
after it indicated it could not be delivered.