Hello @ShoichiroK.00155 (LAC Co., Ltd)​ Thank you for posting on our Community page!

I was able to find an article about this, please see below:

https://support.okta.com/help/s/article/How-can-we-change-our-Office365-federation-from-a-parent-to-a-sub-domain?language=en_US

There has also been a similar question about this, please also see this below:

https://support.okta.com/help/s/question/0D51Y00009QYIWySAP/adding-subdomain-to-our-o365-federated-domain?language=en_US

Thank you for reaching out to our Community and have a great day!

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Ask Us Anything thru 7/14: Okta WIC leadership want to hear from you 

Hello @Paul S. (Okta, Inc.)​ ​

Thank you for your response.

I apologize if my question was a bit unclear. I understand that to use subdomains, the parent domain must be linked when integrating Okta with MS365.

What I am concerned about is the settings in the MS365 sign-on section.

When sample.com is set up with WS-Federation (Auto), users can be created on the MS365 side using sub.sample.com. However, when trying to use apps like Excel from the Okta dashboard, an error occurs.

When sample.com is set up with WS-Federation (Manual), users can be created on the MS365 side using sub.sample.com, and apps like Excel can also be used from the Okta dashboard.

Since the settings are the same, I am curious about the behavior when set to Auto versus Manual. I would appreciate it if you could provide any information on this.