Modern Authentication / OAuth
Using Exchange Online and Outlook not working with of presenting Modern Authentication? Check if OAuth is enabled:
Connect-ExchangeOnline
# check of moderne authenticatie is enabled
Get-OrganizationConfig | Format-Table Name,OAuth* -Auto
#If false, then turn it on.
Set-OrganizationConfig -OAuth2ClientProfileEnabled $true
#Check if enabled. Can take some hours before it's enabled.
Get-OrganizationConfig | Format-Table Name,OAuth* -Auto