Logout session causes nullpointer

I am on a project that uses a Keycloak server (based on Keycloak v.11.0.3) embedded inside of a Spring Boot project. It is essentially based on the ideas of this Baeldung guide. I want to build some functionality so that I can invalidate sessions of a user accross clients. The user comes from an external IdP that Keycloak integrates to. It seems to work, but I am experiencing a weird nullpointer error that I cannot avoid. The code is similar to this:

            KeycloakSession keycloakSession = KeycloakApplication.getSessionFactory().getSession();
            List<RealmModel> realms = getRealmModels(keycloakSession);
            UserSessionModel brokeredUserSession = null;
            for (RealmModel realm : realms) {
                brokeredUserSession = keycloakSession.sessions()
                        .getUserSessionByBrokerSessionId(realm, sessionId);
                if (brokeredUserSession != null) {
                    break;
                }
            }

            if (brokeredUserSession == null) {
                keycloakSession.close();
                return TerminationStatus.EMPTY;
            }

            RealmModel realm = brokeredUserSession.getRealm();
            UserModel user = brokeredUserSession.getUser();
            keycloakSession.users().setNotBeforeForUser(realm, user, Time.currentTime());
            List<UserSessionModel> userSessions = keycloakSession.sessions().getUserSessions(realm, user);
            log.debug("Number of userSessions for user '{}': {}", user.getUsername(), userSessions.size());
            keycloakSession.getContext().setRealm(realm);

            for (UserSessionModel userSession : userSessions) {
                AuthenticationManager.backchannelLogout(keycloakSession, userSession, false);
            }

For some reason, the session is correctly invalidated, but I also get this stacktrace, that makes me suspect that the logout URI is incorrectly constructed. I have tried to set it manually at runtime, but it does not seem to make any difference. Can anyone help me?

java.lang.NullPointerException: null
	at org.keycloak.models.KeycloakUriInfo.getBaseUri(KeycloakUriInfo.java:93) ~[keycloak-server-spi-11.0.3.jar:11.0.3]
	at org.keycloak.services.util.ResolveRelative.resolveRelativeUri(ResolveRelative.java:33) ~[keycloak-services-11.0.3.jar:11.0.3]
	at org.keycloak.services.managers.ResourceAdminManager.getManagementUrl(ResourceAdminManager.java:79) ~[keycloak-services-11.0.3.jar:11.0.3]
	at org.keycloak.services.managers.ResourceAdminManager.logoutClientSessions(ResourceAdminManager.java:147) ~[keycloak-services-11.0.3.jar:11.0.3]
	at org.keycloak.services.managers.ResourceAdminManager.logoutClientSession(ResourceAdminManager.java:143) ~[keycloak-services-11.0.3.jar:11.0.3]
	at org.keycloak.protocol.oidc.OIDCLoginProtocol.backchannelLogout(OIDCLoginProtocol.java:316) ~[keycloak-services-11.0.3.jar:11.0.3]
	at org.keycloak.services.managers.AuthenticationManager.backchannelLogoutClientSession(AuthenticationManager.java:407) ~[keycloak-services-11.0.3.jar:11.0.3]
	at org.keycloak.services.managers.AuthenticationManager.lambda$backchannelLogoutAll$1(AuthenticationManager.java:314) ~[keycloak-services-11.0.3.jar:11.0.3]
	at java.util.HashMap$Values.forEach(HashMap.java:976) ~[?:?]
	at java.util.Collections$UnmodifiableCollection.forEach(Collections.java:1085) ~[?:?]
	at org.keycloak.services.managers.AuthenticationManager.backchannelLogoutAll(AuthenticationManager.java:313) ~[keycloak-services-11.0.3.jar:11.0.3]
	at org.keycloak.services.managers.AuthenticationManager.backchannelLogout(AuthenticationManager.java:247) ~[keycloak-services-11.0.3.jar:11.0.3]
	at org.keycloak.services.managers.AuthenticationManager.backchannelLogout(AuthenticationManager.java:215) ~[keycloak-services-11.0.3.jar:11.0.3]
	at dk.ufst.osm2.keycloak.service.SikkerhedssessionService.lambda$terminateSession$1(SikkerhedssessionService.java:200) ~[classes/:?]
	at java.util.HashMap$Values.forEach(HashMap.java:976) [?:?]
	at java.util.Collections$UnmodifiableCollection.forEach(Collections.java:1085) [?:?]
	at dk.ufst.osm2.keycloak.service.SikkerhedssessionService.terminateSession(SikkerhedssessionService.java:199) [classes/:?]
	at dk.ufst.osm2.keycloak.service.SikkerhedssessionService.getSikkerhedssessionAfslut(SikkerhedssessionService.java:101) [classes/:?]
	at dk.ufst.osm2.keycloak.endpoint.SikkerhedssessionAfslutEndpoint.getSikkerhedssessionAfslut(SikkerhedssessionAfslutEndpoint.java:45) [classes/:?]
	at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]
	at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:?]
	at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]
	at java.lang.reflect.Method.invoke(Method.java:566) ~[?:?]
	at org.apache.cxf.service.invoker.AbstractInvoker.performInvocation(AbstractInvoker.java:179) [cxf-core-3.4.3.jar:3.4.3]
	at org.apache.cxf.jaxws.JAXWSMethodInvoker.performInvocation(JAXWSMethodInvoker.java:66) [cxf-rt-frontend-jaxws-3.4.3.jar:3.4.3]
	at org.apache.cxf.service.invoker.AbstractInvoker.invoke(AbstractInvoker.java:96) [cxf-core-3.4.3.jar:3.4.3]
	at org.apache.cxf.jaxws.AbstractJAXWSMethodInvoker.invoke(AbstractJAXWSMethodInvoker.java:232) [cxf-rt-frontend-jaxws-3.4.3.jar:3.4.3]
	at org.apache.cxf.jaxws.JAXWSMethodInvoker.invoke(JAXWSMethodInvoker.java:85) [cxf-rt-frontend-jaxws-3.4.3.jar:3.4.3]
	at org.apache.cxf.service.invoker.AbstractInvoker.invoke(AbstractInvoker.java:74) [cxf-core-3.4.3.jar:3.4.3]
	at org.apache.cxf.interceptor.ServiceInvokerInterceptor$1.run(ServiceInvokerInterceptor.java:59) [cxf-core-3.4.3.jar:3.4.3]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) [?:?]
	at java.util.concurrent.FutureTask.run(FutureTask.java:264) [?:?]
	at org.apache.cxf.interceptor.ServiceInvokerInterceptor$2.run(ServiceInvokerInterceptor.java:126) [cxf-core-3.4.3.jar:3.4.3]
	at org.apache.cxf.workqueue.SynchronousExecutor.execute(SynchronousExecutor.java:37) [cxf-core-3.4.3.jar:3.4.3]
	at org.apache.cxf.interceptor.ServiceInvokerInterceptor.handleMessage(ServiceInvokerInterceptor.java:131) [cxf-core-3.4.3.jar:3.4.3]
	at org.apache.cxf.phase.PhaseInterceptorChain.doIntercept(PhaseInterceptorChain.java:308) [cxf-core-3.4.3.jar:3.4.3]
	at org.apache.cxf.transport.ChainInitiationObserver.onMessage(ChainInitiationObserver.java:121) [cxf-core-3.4.3.jar:3.4.3]
	at org.apache.cxf.transport.http.AbstractHTTPDestination.invoke(AbstractHTTPDestination.java:265) [cxf-rt-transports-http-3.4.3.jar:3.4.3]
	at org.apache.cxf.transport.servlet.ServletController.invokeDestination(ServletController.java:234) [cxf-rt-transports-http-3.4.3.jar:3.4.3]
	at org.apache.cxf.transport.servlet.ServletController.invoke(ServletController.java:208) [cxf-rt-transports-http-3.4.3.jar:3.4.3]
	at org.apache.cxf.transport.servlet.ServletController.invoke(ServletController.java:160) [cxf-rt-transports-http-3.4.3.jar:3.4.3]
	at org.apache.cxf.transport.servlet.CXFNonSpringServlet.invoke(CXFNonSpringServlet.java:225) [cxf-rt-transports-http-3.4.3.jar:3.4.3]
	at org.apache.cxf.transport.servlet.AbstractHTTPServlet.handleRequest(AbstractHTTPServlet.java:298) [cxf-rt-transports-http-3.4.3.jar:3.4.3]
	at org.apache.cxf.transport.servlet.AbstractHTTPServlet.doPost(AbstractHTTPServlet.java:217) [cxf-rt-transports-http-3.4.3.jar:3.4.3]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:652) [tomcat-embed-core-9.0.45.jar:4.0.FR]
	at org.apache.cxf.transport.servlet.AbstractHTTPServlet.service(AbstractHTTPServlet.java:273) [cxf-rt-transports-http-3.4.3.jar:3.4.3]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) [tomcat-embed-websocket-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:113) [spring-web-5.2.14.RELEASE.jar:5.2.14.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:113) [spring-web-5.2.14.RELEASE.jar:5.2.14.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:113) [spring-web-5.2.14.RELEASE.jar:5.2.14.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:710) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:457) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:384) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:312) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at dk.ufst.osm2.keycloak.config.SoapPortFilter.doFilter(SoapPortFilter.java:39) [classes/:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at dk.ufst.osm2.keycloak.config.LoggingContextFilter.doFilter(LoggingContextFilter.java:27) [classes/:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) [spring-web-5.2.14.RELEASE.jar:5.2.14.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) [spring-web-5.2.14.RELEASE.jar:5.2.14.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) [spring-web-5.2.14.RELEASE.jar:5.2.14.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) [spring-web-5.2.14.RELEASE.jar:5.2.14.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:93) [spring-boot-actuator-2.3.10.RELEASE.jar:2.3.10.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) [spring-web-5.2.14.RELEASE.jar:5.2.14.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) [spring-web-5.2.14.RELEASE.jar:5.2.14.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) [spring-web-5.2.14.RELEASE.jar:5.2.14.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:764) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1707) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) [?:?]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) [?:?]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.45.jar:9.0.45]
	at java.lang.Thread.run(Thread.java:834) [?:?]