Set the Web Service connection settings to Windows Authentication
  1. Open the WebPortal Configuration tool
  2. Go to step 4. FE Database
  3. Set Web Service connection settings to Windows Authentication
  4. Go to step 6. Email Services
  5. Set the desired account and ensure that account has access to the SQL database
OR

Forcibly send emails
  1. Log into WebPortal with Supervisor/Administrator rights
  2. Select Administration > View Email Queue
  3. Click 'Forcibly Send All' or 'Send All Emails'
This issue will be resolved in 7.87 patch 25.