Exchange-SetAuthServerOAuth
Get-AuthServer | where {$_.Name -like "EvoSts*"} | ft name,enabled
Name Enabled
---- -------
EvoSts - 467a7284-2sa1-468c-a793-978ad2f9fc49 True
### Enable evoSTS and OAuth
Set-AuthServer -Identity "EvoSts - 467a7284-2sa1-468c-a793-978ad2f9fc49" -IsDefaultAuthorizationEndpoint $true
Set-OrganizationConfig -OAuth2ClientProfileEnabled $true