500 Internal Server Error

[DefaultExternalContentManager] returned an error. The underlying error was a org.fcrepo.server.errors.GeneralException The message was "Error getting https://e-book.fwf.ac.at/detail_object/o%3A473" .

org.fcrepo.server.errors.HttpServiceNotFoundException: [DefaultExternalContentManager] returned an error.  The underlying error was a org.fcrepo.server.errors.GeneralException  The message was  "Error getting https://e-book.fwf.ac.at/detail_object/o%3A473"  .  
	at org.fcrepo.server.storage.DefaultExternalContentManager.getExternalContent(DefaultExternalContentManager.java:174)
	at org.fcrepo.server.access.dissemination.DisseminationService.assembleDissemination(DisseminationService.java:711)
	at org.fcrepo.server.access.DefaultAccess.getDissemination(DefaultAccess.java:451)
	at org.fcrepo.server.access.FedoraAccessServlet.getDissemination(FedoraAccessServlet.java:707)
	at org.fcrepo.server.access.FedoraAccessServlet.doGet(FedoraAccessServlet.java:427)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:655)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:764)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:369)
	at org.fcrepo.server.security.servletfilters.FilterSetup.doFilter(FilterSetup.java:247)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:381)
	at org.fcrepo.server.security.servletfilters.FilterSetup.doFilter(FilterSetup.java:247)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:381)
	at org.fcrepo.server.security.servletfilters.FilterSetup.doFilter(FilterSetup.java:247)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:381)
	at org.fcrepo.server.security.servletfilters.FilterSetup.doFilter(FilterSetup.java:247)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:381)
	at org.springframework.security.web.access.channel.ChannelProcessingFilter.doFilter(ChannelProcessingFilter.java:109)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:381)
	at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:168)
	at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:237)
	at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:540)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:359)
	at org.apache.coyote.ajp.AjpProcessor.service(AjpProcessor.java:433)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:889)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1735)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.base/java.lang.Thread.run(Thread.java:829)
Caused by: org.fcrepo.server.errors.GeneralException: Error getting https://e-book.fwf.ac.at/detail_object/o%3A473
	at org.fcrepo.server.storage.DefaultExternalContentManager.getFromWeb(DefaultExternalContentManager.java:245)
	at org.fcrepo.server.storage.DefaultExternalContentManager.getFromWeb(DefaultExternalContentManager.java:395)
	at org.fcrepo.server.storage.DefaultExternalContentManager.getExternalContent(DefaultExternalContentManager.java:160)
	... 44 more
Caused by: java.io.IOException: Request failed [404 Not Found]
	at org.fcrepo.common.http.WebClient.execute(WebClient.java:305)
	at org.fcrepo.common.http.WebClient.get(WebClient.java:242)
	at org.fcrepo.common.http.WebClient.get(WebClient.java:173)
	at org.fcrepo.server.storage.DefaultExternalContentManager.getFromWeb(DefaultExternalContentManager.java:195)
	... 46 more