What is the reason for the null error

In my simple example, everything works.
But when I start implementing this in the current project, I get this error. What could be the reason for the conflict?

11-Aug-2021 11:14:27.367 SEVERE [http-nio-8080-exec-46] org.apache.catalina.core.StandardWrapperValve.invoke Servlet.service() for servlet [dispatcher] in context with path [/backend] threw exception
        java.lang.NullPointerException
                at org.keycloak.adapters.KeycloakDeploymentBuilder.internalBuild(KeycloakDeploymentBuilder.java:57)
                at org.keycloak.adapters.KeycloakDeploymentBuilder.build(KeycloakDeploymentBuilder.java:202)
                at org.keycloak.adapters.springboot.KeycloakSpringBootConfigResolver.resolve(KeycloakSpringBootConfigResolver.java:41)
                at org.keycloak.adapters.springsecurity.config.KeycloakSpringConfigResolverWrapper.resolve(KeycloakSpringConfigResolverWrapper.java:40)
                at org.keycloak.adapters.AdapterDeploymentContext.resolveDeployment(AdapterDeploymentContext.java:89)
                at org.keycloak.adapters.springsecurity.filter.KeycloakPreAuthActionsFilter.doFilter(KeycloakPreAuthActionsFilter.java:82)
                at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
                at org.springframework.security.web.csrf.CsrfFilter.doFilterInternal(CsrfFilter.java:100)
                at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
                at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
                at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:66)
                at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
                at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
                at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105)
                at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
                at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56)
                at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
                at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
                at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:215)
                at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:178)
                at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:357)
                at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:270)
                at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
                at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
                at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:200)
                at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
                at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:543)
                at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
                at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
                at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690)
                at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
                at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
                at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:615)
                at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
                at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:818)
                at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1627)
                at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
                at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
                at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
                at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
                at java.base/java.lang.Thread.run(Thread.java:829)