Office 365 smtp 3rd party emailing (relay ) not working, ..., need manually turned on , Veeam Backup agent email reporting

https://forums.veeam.com/veeam-agent-for-windows-f33/smtp-alerts-via-office-365-t58954.html

https://answers.microsoft.com/en-us/msoffice/forum/msoffice_o365admin-mso_other-mso_o365b/office-365-smtp-authentication-failing-even-with/4e2dcfc4-2626-4c3b-a945-9ff1b3404539?page=2

 https://docs.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/authenticated-client-smtp-submission

$<VariableName> = Get-Content "<text file>"

$<VariableName> | foreach {Set-CASMailbox -Identity $_ -SmtpClientAuthenticationDisabled <$true | $false | $null>}

$Allow = Get-Content "C:\My Documents\Allow SMTP AUTH.txt"

$Allow | foreach {Set-CASMailbox -Identity $_ -SmtpClientAuthenticationDisabled $false}

Get-CASMailbox -Identity <MailboxIdentity>  | Format-List SmtpClientAuthenticationDisabled

$Users = Get-CASMailbox -ResultSize unlimited

$Users | where {$_.SmtpClientAuthenticationDisabled -eq $true}

$Users = Get-CASMailbox -ResultSize unlimited

$Users | where {$_.SmtpClientAuthenticationDisabled -eq $false}

$Users = Get-CASMailbox -ResultSize unlimited

$Users | where {$_.SmtpClientAuthenticationDisabled -eq $null}