Why are email addresses marked as "Invalid email"?
All email addresses added to the software are verified via an email validator services to reduce bounce rates and avoid complaints.
Note: An email address that does not exists or is not accepting mails (due to full inbox or any other reason) will be marked as invalid. It includes bad syntax emails, bots and spam traps, fake and disposable emails.
Sometimes, there is no definitive way to determine whether this email is valid or invalid due to the heightened security settings on the domain. In such cases also the email will be marked as invalid.
Sending emails to invalid email address will result in a bounce and also attracts a penalty on our email sending account. Therefore, these emails are not safe for sending.