Why do I see a 400 Bad Request error when trying to sign in to Security Cloud Sign On with my Microsoft account?

Microsoft 365 does not require accounts to have a defined first name and last name. When trying to authenticate with a Microsoft account that does not have a last name, Security Cloud Sign On returns the following error:

400 Bad Request. Unable to create the user. Required properties are missing.

To work around this issue, make sure both first name and last name are defined in your Microsoft 365 account.