Emails are stuck in Pending Send.
1. Verify the User in the From field of the email has their E-mail access type - Outgoing sent to E-mail Router. If it is set as None of Outlook, set it to E-mail Router and Save.
2. Even if that is not the issue you may have to click Approve E-mail in the top ribbon tool bar to make sure the e-mail is approved. If you did have to do step one you will absolutely have to do step 2.
3. If that is not the issue, click on the Default Queue for the User in the From field of the email.
4. If no email is listed in the Queue, add the same email address as the User and Save.
5. Click Approve E-mail.
5. If that is not the issue, put in a support ticket and ask Support to verify that the Email service is started on the server.