Is anyone else seeing this? Are there any known remedies?
Yahoo have always had rate limits and cumulative counters and in every company where I managed outbound mail servers from data-centers I had to set up separate queues and destination limits for their domain or I would get the same effect you are seeing. It does not show up right away. They have always had some of the strictest rate limit policies.
The only remedy I know of is to set up queues and rate limits specific to their domain and setting gradual back-off timers. Distributing the queue into multiple outbound servers or data-centers will not work if using the same sending domain.
I am assuming you have configured SPF, DKIM, and a published DMARC policy and have checked your reputation in their sender hub [1][2] and have warmed up your IP and email address reputation (as you have it in their error message).
Is anyone else seeing this? Are there any known remedies?
Yahoo have always had rate limits and cumulative counters and in every company where I managed outbound mail servers from data-centers I had to set up separate queues and destination limits for their domain or I would get the same effect you are seeing. It does not show up right away. They have always had some of the strictest rate limit policies.
The only remedy I know of is to set up queues and rate limits specific to their domain and setting gradual back-off timers. Distributing the queue into multiple outbound servers or data-centers will not work if using the same sending domain.
I am assuming you have configured SPF, DKIM, and a published DMARC policy and have checked your reputation in their sender hub [1][2] and have warmed up your IP and email address reputation (as you have it in their error message).
[1] - https://senders.yahooinc.com/
[2] - https://senders.yahooinc.com/faqs/