InformationIf this setting is enabled then you will not be able to configure mutual authentication TLS, referred to as 'External send connector authentication: Domain Security' in this baseline.
Basic authentication sends credentials across the network in plaintext. TLS helps protect credentials from interception by unauthorized users.
SolutionTo implement the recommended state, execute the following PowerShell cmdlet:
set-SendConnector -identity -IgnoreSTARTTLS: $false