Verizon Media PH01 errors occur primarily due to email content being flagged as potential phishing. Causes include compromised accounts, links to malicious sites, suspicious content, poor IP reputation, and issues with email authentication protocols (SPF, DKIM, DMARC). Resolution involves regular security audits, content scanning, maintaining an up-to-date understanding of email best practices, avoiding URL shorteners, implementing strict DMARC policies, ensuring SPF records are accurate, monitoring sender reputation, cleaning email lists, and avoiding sudden spikes in sending volume. Issues stemming from third-party senders may also cause this error.