About SSO with Rstudio rserver pro 1.4v

I had been trying to do SSO using OpenID connect with RStudio Server Pro 1.4 Preview . I had followed the steps from this url https://docs.rstudio.com/ide/server-pro/1.4.1100-3/authenticating-users.html#enabling-openid-connect but I was unable to proceed from OpenID Issuer and Well-Known configuration . when I saw my log than following error occurs

06 Jan 2021 04:04:29 [rserver-monitor] ERROR 06 Jan 2021 04:04:29 [rserver] ERROR OpenID failed with error: 400 Bad Request: {"code":"BadRequest","message":"The server did not understand the operation that was requested.","type":"client"}; LOGGED FROM: void rstudio::server::openid_auth::{anonymous}::writeResponse(rstudio_boost::shared_ptrrstudio::core::http::AsyncConnection, const rstudio::core::http::Response&) src/cpp/server/openid_auth/ServerOpenIDAuth.cpp:147|||
06 Jan 2021 04:04:29 [rserver-monitor] ERROR 06 Jan 2021 04:04:29 [rserver] ERROR rserver-openid: OpenID handling error trying to creating provider: 400 Bad Request: {"code":"BadRequest","message":"The server did not understand the operation that was requested.","type":"client"}; LOGGED FROM: void rstudio::server::ProcessMonitor::onProcessStderr(rstudio::server::ProcessMonitor::Process, const string&) src/cpp/server/ServerProcessMonitor.cpp:247|||

I am very confused here . Can anyone help me

I had tried to explain it in steps as follow
I had been trying to do SSO using OpenID connect with RStudio Server Pro 1.4 Preview .
I had done the following steps but got an error .
I looked at the error log, but I don't understand the contents. If there is something missing then please let me know.

  1. At first I installed Rstudio Server Pro 1.4 Preview in AWS EC2 .
  2. http: // : 8787 will display the login screen(Rstudio Server login) and login is OK
  3. Then I enter the following components in /etc/rstudio/rserver.conf. OP is AWS Cognito.
    auth-openid=1
    auth-openid-issuer=https://cognito-idp.XXXXXXXXXXXXXX.amazonaws.com/ap-northeast-1_XXXXXXXX/.well-known/openid-configuration
  4. I enter client-id and client-secret in /etc/rstudio/openid-client-secret
    client-id=XXXXXXXXXXXXXXXXXXXXXXXX
    client-secret=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
    5.rstudio restart
  5. Now http: // : 8787 will display the login screen(OpenId Connect login)
  6. When I clicked in Sign in with OpenID link then I got an error.
  7. Server Log

06 Jan 2021 04:04:29 [rserver-monitor] ERROR 06 Jan 2021 04:04:29 [rserver] ERROR OpenID failed with error: 400 Bad Request: {"code":"BadRequest","message":"The server did not understand the operation that was requested.","type":"client"}; LOGGED FROM: void rstudio::server::openid_auth::{anonymous}::writeResponse(rstudio_boost::shared_ptrrstudio::core::http::AsyncConnection, const rstudio::core::http::Response&) src/cpp/server/openid_auth/ServerOpenIDAuth.cpp:147|||
06 Jan 2021 04:04:29 [rserver-monitor] ERROR 06 Jan 2021 04:04:29 [rserver] ERROR rserver-openid: OpenID handling error trying to creating provider: 400 Bad Request: {"code":"BadRequest","message":"The server did not understand the operation that was requested.","type":"client"}; LOGGED FROM: void rstudio::server::ProcessMonitor::onProcessStderr(rstudio::server::ProcessMonitor::Process, const string&) src/cpp/server/ServerProcessMonitor.cpp:247|||