ADFS service start failure

Dear Experts,

We are not able to restart adfs service after activating new SSL certificate with "Set-AdfsSslCertificate -Thumbprint 'XXXXXXXXXXXACF1D94XXXXXXXXXXXXXXXXX" command. Below is the error we receive:

on powershell:

"Set-AdfsSslCertificate : Could not connect to net.tcp://localhost:1600/policy. The connection attempt lasted for a time span of 00:00:02.0287450. TCP error code 10061: No connection could be made because the target machine actively refused it 127.0.0.1:1600.

At line:1 char:1

• Set-AdfsSslCertificate -Thumbprint 'ACF ...
• CategoryInfo : OpenError: (:) [Set-AdfsSslCertificate], EndpointNotFoundException
• FullyQualifiedErrorId : Could not connect to net.tcp://localhost:1600/policy. The connection attempt lasted for a time span of 00:00:02.0287450. TCP error code 10061: No connection could be made because the target machine actively refused it 127.0.0.1:1600. ,Micr

osoft.IdentityServer.Management.Commands.SetSslCertificateCommand"

on event viewer and server manager:

There was an error in enabling endpoints of Federation Service. Fix configuration errors using PowerShell cmdlets and restart the Federation Service. 

Additional Data 

Exception details: 

System.ArgumentNullException: Value cannot be null.

Parameter name: certificate

   at System.IdentityModel.Tokens.X509SecurityToken..ctor(X509Certificate2 certificate, String id, Boolean clone, Boolean disposable)

   at Microsoft.IdentityServer.Service.Configuration.MSISSecurityTokenServiceConfiguration.Create(Boolean forSaml, Boolean forPassive)

   at Microsoft.IdentityServer.Service.Policy.PolicyServer.Service.ProxyPolicyServiceHost.ConfigureWIF()

   at Microsoft.IdentityServer.Service.SecurityTokenService.MSISConfigurableServiceHost.Configure()

   at Microsoft.IdentityServer.Service.Policy.PolicyServer.Service.ProxyPolicyServiceHost.Create()

   at Microsoft.IdentityServer.ServiceHost.STSService.StartProxyPolicyStoreService(ServiceHostManager serviceHostManager)

   at Microsoft.IdentityServer.ServiceHost.STSService.OnStartInternal(Boolean requestAdditionalTime)

Would you please help?