Descriptions: First thing first, there is no option in mailbox properties to restrict a specific user from sending email outside the organization if you are using Office365 online exchange server.Solved – Cannot uncheck “Only trust email from addresses in my safe senders and domains list and safe mailing lists” office365 Junk email A user complained that valid good email was being sent to the Junk email folder on outlook on the web.It works on most current computers or devices and solves many of the common problems with sending email such as relaying denied errors or blacklisting issues. AuthSMTP is the outgoing SMTP email service for your e-commerce website, mailing list or email program.