Manually Verify an Email
In order to send email out of your system, your users will need to verify they have access to the email they are sending emails from.
This can be done in Settings > Mail Merge Profile. It will only need to be done once. Here are the steps and further instructions: Verify Your Email Address to Send Email.
If your contacts are experiencing difficulty receiving the email to verify their email, you can do that for them. You will need to sign into your admin panel and adjust this URL to be set to your domain: https://yourdomain.com/wlcrm/VerifyEmail.aspx. Complete the form and submit.