Looking for Yahoo eMail contact

[zwicky at yahoo-inc.com (Elizabeth Zwicky)]

http://postmaster.yahoo.com,?click on "Contact Us" at the top since your question isn't one of the giant ones in the middle of the page.
Elizabeth Zwicky 

    On Monday, January 11, 2016 4:28 AM, Marc Storck <mstorck at voipgate.com> wrote:
 

 Hello,

I?m looking for a Yahoo email administrator who could contact me offlist.

I have a customer with a clean record that is getting thsi error:

Error: "421 4.7.1 [TS03] All messages from x.x.x.x permanently deferred" when sending email to Yahoo

The customer is a local non-profit and sends a very limited amount of emails to members, suppliers and other contacts. Mailing-lists are only used to contact members of the NPO.

I checked the recommendation listed at
https://help.yahoo.com/kb/postmaster/SLN3436.html

and checked his IP address on several ?multi-rbl? lookup sites. All looks clean.

So I need more input to understand what we need to correct.

Thank you very much in advance.

Best regards,

Marc