Assumptions:

Assuming you have AAD setup properly and licensed properly. Machine is joined to AAD but you cannot login to Windows 10 with OKTA credentials.

Fix: You must enable OKTA as a CSP and whitelist the OKTA URLs (very important and what caused me headaches).

In Azure Endpoint Manager:

Devices>Windows>Configurations Profiles

Create new Profile

Platform: Windows 10 and Later

Profile Type: Template

Template Name: Custom

Name: Whatever you want called mine "Windows 10 Enable Web Login"

Configuration settings: (OMA-URI Settings)

ADD:

Name: Web Sign-In

OMA-URI: ./Device/Vendor/MSFT/Policy/Config/Authentication/EnableWebSignIn

Data type: Integer

Value: 1

Name: Prefered Azure Ad Tenant

OMA-URI: ./Device/Vendor/MSFT/Policy/Config/Authentication/PreferredAadTenantDomainName

Data type: String

Value: {Azure custom domain} example: example.com (If you have a custom domain in Azure)

Name: Web Sign In Allowed URLs

OMA-URI: ./Vendor/MSFT/Policy/Config/Authentication/ConfigureWebSignInAllowedUrls

Data type: String

Value: login.microsoft.com;login.okta.com;{custom domain for OKTA aka cname}

*Caveat here I am still testing Smartcard login it is not functioning at the moment, it maybe URI issue*

Next

Assignments:

You will want to create a group and add the AAD joined computer to it so it will get this policy.

Applicability Rules:

This is up to you how and if you want it filtered.

Next

Create

References:

https://docs.microsoft.com/en-us/mem/intune/configuration/custom-settings-windows-10

https://docs.microsoft.com/en-us/windows/client-management/mdm/policy-csp-authentication

https://docs.microsoft.com/en-us/windows/security/identity-protection/hello-for-business/hello-feature-pin-reset#configure-web-sign-in-allowed-urls-for-third-party-identity-providers-on-azure-ad-joined-devices

Errors:

Web signin error: We Can't open that page right now. For security reasons, you'll need to visit the page from a browser or different device..... 

"ConfigureWebSignInAllowedUrls" above now needs to be configured per the below CVE

 > https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-27092