Even with dedicated IPs and low direct spam complaints, Yahoo may block emails due to various factors related to sender reputation, engagement, authentication, content, and infrastructure. Key areas to examine include: low engagement rates (opens/clicks), poor list hygiene, sudden changes in sending patterns or volume, incomplete email authentication (SPF, DKIM, DMARC), spam-triggering content, potential blacklisting of the IP address (even if dedicated), inconsistencies in sending schedules, and lack of feedback loop monitoring. Yahoo's filters are particularly sensitive; therefore, a holistic approach to email deliverability is necessary, encompassing technical setup, sending behavior, and content strategy.