Verify Admin user in App settings > Click update again to confirm.

Note. If your admin username is email prefix then please ensure this email address is not associated for other users.

Go to App settings > Click On User Authentication.

Optional:

Some times few Inactive users may not granted license / access via SAML / SSO due to login sessions not expired.

Go to Authentication methods > SAML Configuration > Edit > Un check / disable Remember user logins > Save.

If your using third-party SAML plugins like MiniOrange / Re:Solution you can skip On User Authentication feature:

Please use group settings in IDP configuration: