When the Robot is trying to access Outlook for sending or reading emails, a security warning pop-up appears : "A program is trying to access email address information stored in Outlook".
These security warnings appear when a program attempts to access your contact information in the Outlook Address Book, or attempts to send email on your behalf.
By default, only COM add-ins are trusted programs. The email administrator may have allowed specific add-ins by adding them to a "Trusted add-ins" list. Any other program is not trusted, and a security warning appears because of the potential risk that the program is malicious and designed to use Outlook to spread viruses.
From Trust Center -> Programmatic Access settings set the programmatic access to " Never warn me about suspicious activity (not recommended)" .
For more details check Program Is Trying To Send An Email Message On Your Behalf .