Troubleshooting B2B email quarantine issues with new dedicated IPs and strict security settings involves several key strategies. First, ensure proper email authentication (SPF, DKIM, DMARC) is in place and correctly configured. IP warming is crucial, starting with small email volumes to engaged subscribers and gradually increasing over time, while monitoring sender reputation. Also, consider that recipient-side configurations, such as strict spam rules or specific email provider settings (e.g., Mimecast), may require whitelisting the new IP by the recipient's IT department. Informing customers of platform changes and providing whitelisting instructions can help. Utilizing email warming tools, monitoring deliverability metrics, and exploring certifications like Return Path can further improve deliverability. A comprehensive deliverability checklist covering authentication, IP warming, list hygiene, content optimization, and continuous monitoring is essential.