A Program is trying to Send an email on your Behalf 

outlook-security-warning-send-email-allow-deny-progress-bar

For this, the following options should then be set:

This results in the following Registry keys being set:

Key: HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\<version>\Outlook\Security
Value name: AdminSecurityMode
Value type: REG_DWORD
Value: 3

Key: HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\<version>\Outlook\Security
Value name: PromptOOMSend
Value name: PromptOOMAddressBookAccess
Value name: PromptOOMAddressInformationAccess
Value name: PromptOOMMeetingTaskRequestResponse
Value name: PromptOOMSaveAs
Value name: PromptOOMFormulaAccess
Value name: PromptSimpleMAPISend
Value name: PromptSimpleMAPINameResolve
Value name: PromptSimpleMAPIOpenMessage
Value type: REG_DWORD
Value: 2

disableprogrammaticsecurity.zip

https://www.msoutlook.info/question/883

Outlook Version Reference

Version Name Version Number
Outlook 97 8.0
Outlook 98 8.5
Outlook 2000 9.0
Outlook XP/2002 10.0
Outlook 2003 11.0
Outlook 2007 12.0
Outlook 2010 14.0
Outlook 2013 15.0
Outlook 2016 16.0
Outlook 2019 16.0
Office 365 16.0