Okta single logut status:AuthnFailed

Hi,
I am trying to integrate okta into my web application. okta SSO works fine. When I try to do Single Logout okta gives AuthnFailed status.
I am using self-signed certificates for a local server. My server running on http://localhost:3000(http://192.xxx.xx.x:3000). I am initiating single log out from a service provider. I configured single logout url in okta dashboard as like http://192.xxx.xx.x:3000/logout/callback, uploaded self-signed certificate in .cer format and given issuer of a service provider in okta dashboard. I configured okta configuration well.

Below is SLO response status:

<saml2p:Status 
    xmlns:saml2p="urn:oasis:names:tc:SAML:2.0:protocol">
    <saml2p:StatusCode 
        Value="urn:oasis:names:tc:SAML:2.0:status:AuthnFailed"/>

</saml2p:Status>