Yahoo mail blocking my partners IPs.

jeffnascimento - Jan 24, 2023 at 08:51 AM


Every time a specific partner, whos using King Host as email provider, sends me a message, he gets that error. I could not find anything on Yahoo configs to whitelist that IP or his domain. 

<***@***>: host[] said:
    553 5.7.2 [TSS09] All messages from will be permanently
    deferred; Retrying will NOT succeed. See (in reply to MAIL FROM command)

Any clue on how to solve that?

Windows / Chrome