title: java.util.concurrent.TimeoutException: Did not observe any item or terminal signal within 10000ms in 'map' (and no fallback has been configured)
body: <p>I'm building the Spring Boot Admin code and getting the below error.</p>
  <p>pom.xml</p>
  <pre><code>&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?&gt;
  &lt;project xmlns=&quot;http://maven.apache.org/POM/4.0.0&quot; xmlns:xsi=&quot;http://www.w3.org/2001/XMLSchema-instance&quot;
      xsi:schemaLocation=&quot;http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd&quot;&gt;
      &lt;modelVersion&gt;4.0.0&lt;/modelVersion&gt;
      &lt;parent&gt;
          &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
          &lt;artifactId&gt;spring-boot-starter-parent&lt;/artifactId&gt;
          &lt;version&gt;2.4.2&lt;/version&gt;
          &lt;relativePath/&gt; &lt;!-- lookup parent from repository --&gt;
      &lt;/parent&gt;
      &lt;groupId&gt;com.example&lt;/groupId&gt;
      &lt;artifactId&gt;admin-server&lt;/artifactId&gt;
      &lt;version&gt;0.0.1-SNAPSHOT&lt;/version&gt;
      &lt;name&gt;admin-server&lt;/name&gt;
      &lt;description&gt;Demo project for Spring Boot&lt;/description&gt;
      &lt;properties&gt;
          &lt;java.version&gt;1.8&lt;/java.version&gt;
          &lt;spring-boot-admin.version&gt;2.3.1&lt;/spring-boot-admin.version&gt;
          &lt;spring-cloud.version&gt;2020.0.2&lt;/spring-cloud.version&gt;
      &lt;/properties&gt;
      &lt;dependencies&gt;
          &lt;!-- Spring Boot Admin --&gt;
          &lt;dependency&gt;
              &lt;groupId&gt;de.codecentric&lt;/groupId&gt;
              &lt;artifactId&gt;spring-boot-admin-starter-server&lt;/artifactId&gt;
          &lt;/dependency&gt;
          &lt;dependency&gt;
              &lt;groupId&gt;de.codecentric&lt;/groupId&gt;
              &lt;artifactId&gt;spring-boot-admin-server-ui&lt;/artifactId&gt;
          &lt;/dependency&gt;
          &lt;dependency&gt;
              &lt;groupId&gt;org.springframework.cloud&lt;/groupId&gt;
              &lt;artifactId&gt;spring-cloud-starter-bootstrap&lt;/artifactId&gt;
          &lt;/dependency&gt;
          &lt;dependency&gt;
              &lt;groupId&gt;org.springframework.cloud&lt;/groupId&gt;
              &lt;artifactId&gt;spring-cloud-starter-config&lt;/artifactId&gt;
          &lt;/dependency&gt;
          &lt;dependency&gt;
              &lt;groupId&gt;org.springframework.cloud&lt;/groupId&gt;
              &lt;artifactId&gt;spring-cloud-starter-netflix-eureka-client&lt;/artifactId&gt;
          &lt;/dependency&gt;
          
          &lt;!-- Third-party librairies --&gt;
          &lt;dependency&gt;
              &lt;groupId&gt;org.jolokia&lt;/groupId&gt;
              &lt;artifactId&gt;jolokia-core&lt;/artifactId&gt;
          &lt;/dependency&gt;
  
          &lt;dependency&gt;
              &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
              &lt;artifactId&gt;spring-boot-starter-test&lt;/artifactId&gt;
              &lt;scope&gt;test&lt;/scope&gt;
          &lt;/dependency&gt;
      &lt;/dependencies&gt;
      &lt;dependencyManagement&gt;
          &lt;dependencies&gt;
              &lt;dependency&gt;
                  &lt;groupId&gt;org.springframework.cloud&lt;/groupId&gt;
                  &lt;artifactId&gt;spring-cloud-dependencies&lt;/artifactId&gt;
                  &lt;version&gt;${spring-cloud.version}&lt;/version&gt;
                  &lt;type&gt;pom&lt;/type&gt;
                  &lt;scope&gt;import&lt;/scope&gt;
              &lt;/dependency&gt;
              &lt;dependency&gt;
                  &lt;groupId&gt;de.codecentric&lt;/groupId&gt;
                  &lt;artifactId&gt;spring-boot-admin-dependencies&lt;/artifactId&gt;
                  &lt;version&gt;${spring-boot-admin.version}&lt;/version&gt;
                  &lt;type&gt;pom&lt;/type&gt;
                  &lt;scope&gt;import&lt;/scope&gt;
              &lt;/dependency&gt;
          &lt;/dependencies&gt;
      &lt;/dependencyManagement&gt;
  
      &lt;build&gt;
          &lt;plugins&gt;
              &lt;plugin&gt;
                  &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
                  &lt;artifactId&gt;spring-boot-maven-plugin&lt;/artifactId&gt;
              &lt;/plugin&gt;
          &lt;/plugins&gt;
      &lt;/build&gt;
  
  &lt;/project&gt;
  </code></pre>
  <p>bootstrap.yml</p>
  <pre><code>spring:
    cloud:
      config:
        enabled: true
        uri: http://localhost:9296
        
    application:
      name: admin-server
      
  server:
    port: 9090
    
  eureka:
    client:
      register-with-eureka: true
      fetch-registry: true
    instance:
      hostname: localhost
      prefer-ip-address: true
  </code></pre>
  <p>AdminServerApplication.java</p>
  <pre><code>@SpringBootApplication
  @EnableAdminServer
  @EnableEurekaClient
  public class AdminServerApplication {
  
      public static void main(String[] args) {
          SpringApplication.run(AdminServerApplication.class, args);
      }
  
  }
  </code></pre>
  <p>Error:</p>
  <pre><code>2021-05-04 13:39:12.290  WARN 36752 --- [ctor-http-nio-1] io.netty.resolver.dns.DnsQueryContext    : Received a mismatching DNS response: DatagramDnsResponse(from: /172.30.160.1:53, to: /0:0:0:0:0:0:0:0:56414, 52280, QUERY(0), NoError(0), RD RA)
      DefaultDnsQuestion(XXXXXXXXorg. IN A)
      DefaultDnsRawRecord(XXXXXXXXorg. 171 IN A 4B)
      DefaultDnsRawRecord(OPT flags:0 udp:4096 0B)
  2021-05-04 13:39:12.882  INFO 36752 --- [           main] com.example.demo.AdminServerApplication  : Started AdminServerApplication in 6.649 seconds (JVM running for 7.875)
  2021-05-04 13:39:17.355  WARN 36752 --- [ctor-http-nio-1] io.netty.resolver.dns.DnsQueryContext    : Received a mismatching DNS response: DatagramDnsResponse(from: /172.30.160.1:53, to: /0:0:0:0:0:0:0:0:56414, 3238, QUERY(0), NoError(0), RD AA RA)
      DefaultDnsQuestion(XXXXXXXXorg. IN CNAME)
      DefaultDnsRawRecord(corp.mastercard.org. 3600 IN SOA 56B)
      DefaultDnsRawRecord(OPT flags:0 udp:4000 0B)
  2021-05-04 13:39:22.211  INFO 36752 --- [     parallel-5] d.c.b.a.server.services.StatusUpdater    : Couldn't retrieve status for Instance(id=162455d08d2a, version=0, registration=Registration(name=CONFIG-SERVER, managementUrl=http://XXXXXXXXorg:9296/actuator, healthUrl=http://XXXXXXXXorg:9296/actuator/health, serviceUrl=http://XXXXXXXXorg:9296, source=discovery), registered=true, statusInfo=StatusInfo(status=UNKNOWN, details={}), statusTimestamp=2021-05-04T08:09:12.195Z, info=Info(values={}), endpoints=Endpoints(endpoints={health=Endpoint(id=health, url=http://XXXXXXXXorg:9296/actuator/health)}), buildVersion=null, tags=Tags(values={}))
  
  java.util.concurrent.TimeoutException: Did not observe any item or terminal signal within 10000ms in 'map' (and no fallback has been configured)
      at reactor.core.publisher.FluxTimeout$TimeoutMainSubscriber.handleTimeout(FluxTimeout.java:294) ~[reactor-core-3.4.2.jar:3.4.2]
      Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: 
  Error has been observed at the following site(s):
      |_ checkpoint ⇢ Request to GET health [DefaultWebClient]
  Stack trace:
          at reactor.core.publisher.FluxTimeout$TimeoutMainSubscriber.handleTimeout(FluxTimeout.java:294) ~[reactor-core-3.4.2.jar:3.4.2]
          at reactor.core.publisher.FluxTimeout$TimeoutMainSubscriber.doTimeout(FluxTimeout.java:279) ~[reactor-core-3.4.2.jar:3.4.2]
          at reactor.core.publisher.FluxTimeout$TimeoutTimeoutSubscriber.onNext(FluxTimeout.java:418) ~[reactor-core-3.4.2.jar:3.4.2]
          at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java:79) ~[reactor-core-3.4.2.jar:3.4.2]
          at reactor.core.publisher.MonoDelay$MonoDelayRunnable.run(MonoDelay.java:119) ~[reactor-core-3.4.2.jar:3.4.2]
          at reactor.core.scheduler.SchedulerTask.call(SchedulerTask.java:68) ~[reactor-core-3.4.2.jar:3.4.2]
          at reactor.core.scheduler.SchedulerTask.call(SchedulerTask.java:28) ~[reactor-core-3.4.2.jar:3.4.2]
          at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[na:1.8.0_171]
          at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180) ~[na:1.8.0_171]
          at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293) ~[na:1.8.0_171]
          at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) ~[na:1.8.0_171]
          at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) ~[na:1.8.0_171]
          at java.lang.Thread.run(Thread.java:748) ~[na:1.8.0_171]
  </code></pre>