title: Why is my Springboot application not starting up?
body: <p>I bootstrapped the springboot application with JHipster but I have not been able to get it start up . It says build success but won't start up on a server . There is an embedded tomcat server added to the POM.XML , what could be wrong ?</p>
  <pre><code>
  Caused by: java.lang.IllegalArgumentException: Unable to resolve Configuration with the provided Issuer of &quot;http://localhost:9080/auth/realms/jhipster&quot;
      at org.springframework.security.oauth2.client.registration.ClientRegistrations.getBuilder(ClientRegistrations.java:221)
      at org.springframework.security.oauth2.client.registration.ClientRegistrations.fromIssuerLocation(ClientRegistrations.java:145)
      at org.springframework.boot.autoconfigure.security.oauth2.client.OAuth2ClientPropertiesRegistrationAdapter.getBuilderFromIssuerIfPossible(OAuth2ClientPropertiesRegistrationAdapter.java:83)
      at org.springframework.boot.autoconfigure.security.oauth2.client.OAuth2ClientPropertiesRegistrationAdapter.getClientRegistration(OAuth2ClientPropertiesRegistrationAdapter.java:59)
      at org.springframework.boot.autoconfigure.security.oauth2.client.OAuth2ClientPropertiesRegistrationAdapter.lambda$getClientRegistrations$0(OAuth2ClientPropertiesRegistrationAdapter.java:53)
      at java.base/java.util.HashMap.forEach(HashMap.java:1425)
      at org.springframework.boot.autoconfigure.security.oauth2.client.OAuth2ClientPropertiesRegistrationAdapter.getClientRegistrations(OAuth2ClientPropertiesRegistrationAdapter.java:52)
      at org.springframework.boot.autoconfigure.security.oauth2.client.servlet.OAuth2ClientRegistrationRepositoryConfiguration.clientRegistrationRepository(OAuth2ClientRegistrationRepositoryConfiguration.java:49)
      at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
      at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.base/java.lang.reflect.Method.invoke(Method.java:564)
      at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154)
      ... 118 common frames omitted
  Caused by: org.springframework.web.client.ResourceAccessException: I/O error on GET request for &quot;http://localhost:9080/auth/realms/jhipster/.well-known/openid-configuration&quot;: Connection refused: connect; nested exception is java.net.ConnectException: Connection refused: connect
      at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:785)
      at org.springframework.web.client.RestTemplate.exchange(RestTemplate.java:670)
      at org.springframework.security.oauth2.client.registration.ClientRegistrations.lambda$oidc$0(ClientRegistrations.java:156)
      at org.springframework.security.oauth2.client.registration.ClientRegistrations.getBuilder(ClientRegistrations.java:209)
      ... 130 common frames omitted
  Caused by: java.net.ConnectException: Connection refused: connect
      at java.base/sun.nio.ch.Net.connect0(Native Method)
      at java.base/sun.nio.ch.Net.connect(Net.java:574)
      at java.base/sun.nio.ch.Net.connect(Net.java:563)
      at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:588)
      at java.base/java.net.Socket.connect(Socket.java:648)
      at java.base/java.net.Socket.connect(Socket.java:597)
      at java.base/sun.net.NetworkClient.doConnect(NetworkClient.java:182)
      at java.base/sun.net.www.http.HttpClient.openServer(HttpClient.java:474)
      at java.base/sun.net.www.http.HttpClient.openServer(HttpClient.java:569)
      at java.base/sun.net.www.http.HttpClient.&lt;init&gt;(HttpClient.java:242)
      at java.base/sun.net.www.http.HttpClient.New(HttpClient.java:341)
      at java.base/sun.net.www.http.HttpClient.New(HttpClient.java:362)
      at java.base/sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:1261)
      at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1194)
      at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:1082)
      at java.base/sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:1016)
      at org.springframework.http.client.SimpleBufferingClientHttpRequest.executeInternal(SimpleBufferingClientHttpRequest.java:76)
      at org.springframework.http.client.AbstractBufferingClientHttpRequest.executeInternal(AbstractBufferingClientHttpRequest.java:48)
      at org.springframework.http.client.AbstractClientHttpRequest.execute(AbstractClientHttpRequest.java:66)
      at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:776)
      ... 133 common frames omitted
  
                  
                           
  </code></pre>