Resolved -
Yahoo has lifted the false positive blocks. Sadly we do not receive any specific information to share.
>>>> Thank you very much for your patience while we were investigating your issue. I am following up on your recent request. Great news! We've fixed the issue and everything should be working now. If you see any new (PH01) errors please provide the recipient's address and the date of the message and we'll be happy to take a look. Per our privacy policies, we can’t give out any additional information regarding IP activity or domain status. Let me know if you have any other questions or concerns.
Thank you again for contacting Yahoo Postmaster. Warm regards,
Yahoo Postmaster >>>>
Apr 22, 18:23 CEST
Identified -
We experience some non documented blocks of IP numbers across the infrastructure. In contact with Yahoo Customer care to mitigate as fast as possible. Sorry for any inconvenience
Apr 20, 09:00 CEST