There are multiple reasons why emails may be classified as junk:
Sender Reputation: If the sender has a poor reputation due to previous spam complaints or blacklisting, their emails are more likely to be flagged. Email Content: Certain keywords and phrases (like "free," "urgent," and "limited offer") can trigger spam filters, especially when used excessively. Authentication Issues: Emails lacking proper authentication protocols such as SPF, DKIM, and DMARC are more likely to be marked as spam. User Behavior: High unsubscribe rates, low engagement rates, and frequent deletions without reading can signal to ESPs that your emails are unwanted.