What is a common challenge of sending emails to unverified lists?

Sending emails to unverified lists often leads to a higher risk of spam complaints. When a recipient receives an email that they did not opt-in for or do not recognize, they are more likely to mark it as spam. This can negatively impact the sender's reputation and deliverability. Many email service providers monitor spam complaint rates, and if they become too high, they may restrict the sender's ability to reach inboxes or even suspend their account.

In contrast, sending emails to verified lists helps ensure that recipients have shown interest and are more likely to welcome communication, resulting in better engagement and lower spam complaints. Unverified lists lack this critical aspect of consent and relevance, making them a poor choice for effective email marketing.