XSite replication fails with NPE

^[[33m22:31:16,771 WARN  [org.infinispan.remoting.transport.jgroups.CommandAwareRpcDispatcher] (jgroups-3,_localhost:LON) ISPN000071: Caught exception when handling command SingleXSiteRpcCommand{command=PrepareCommand {modifications=[Pu\
tKeyValueCommand{key=WrappedByteArray{bytes=0x03033C000000156C6F63616C686F73742F6A77732D73657373696F6E102A292B7B4614A4729C81EC6B75F575F4, hashCode=1891322011}, value=WrappedByteArray{bytes=0x03033B191357DE3C65438E996982DF7DC54E540000016\
0E1FBFF7400, hashCode=0}, flags=[], putIfAbsent=false, valueMatcher=MATCH_ALWAYS, metadata=EmbeddedExpirableMetadata{lifespan=-1, maxIdle=-1, version=NumericVersion{version=4294967297}}, successful=true, topologyId=-1}], onePhaseCommit=\
true, retried=false, gtx=GlobalTx:e909705c-f1b0-be2f-5128-f2bdd627b8ea:1, cacheName='default', topologyId=-1}}: java.lang.NullPointerException                                                                                               
        at org.infinispan.xsite.BackupReceiverRepositoryImpl.isBackupForRemoteCache(BackupReceiverRepositoryImpl.java:102)                                                                                                                   
        at org.infinispan.xsite.BackupReceiverRepositoryImpl.getBackupReceiver(BackupReceiverRepositoryImpl.java:75)                                                                                                                         
        at org.infinispan.remoting.inboundhandler.GlobalInboundInvocationHandler.handleFromRemoteSite(GlobalInboundInvocationHandler.java:96)                                                                                                
        at org.infinispan.remoting.transport.jgroups.CommandAwareRpcDispatcher.executeCommandFromRemoteSite(CommandAwareRpcDispatcher.java:175)                                                                                              
        at org.infinispan.remoting.transport.jgroups.CommandAwareRpcDispatcher.handle(CommandAwareRpcDispatcher.java:149)                                                                                                                    
        at org.jgroups.blocks.RequestCorrelator.handleRequest(RequestCorrelator.java:383)                                                                                                                                                    
        at org.jgroups.blocks.RequestCorrelator.dispatch(RequestCorrelator.java:356)                                                                                                                                                         
        at org.jgroups.blocks.RequestCorrelator.receiveMessage(RequestCorrelator.java:307)                                                                                                                                                   
        at org.jgroups.blocks.MessageDispatcher$ProtocolAdapter.up(MessageDispatcher.java:582)                                                                                                                                               
        at org.jgroups.JChannel.up(JChannel.java:816)                                                                                                                                                                                        
        at org.jgroups.fork.ForkProtocolStack.up(ForkProtocolStack.java:134)                                                                                                                                                                 
        at org.jgroups.stack.Protocol.up(Protocol.java:340)                                                                                                                                                                                  
        at org.jgroups.protocols.FORK.up(FORK.java:134)                                                                                                                                                                                      
        at org.jgroups.protocols.relay.RELAY2.deliver(RELAY2.java:645)                                                                                                                                                                       
        at org.jgroups.protocols.relay.RELAY2.route(RELAY2.java:542)                                                                                                                                                                         
        at org.jgroups.protocols.relay.RELAY2.handleMessage(RELAY2.java:517)                                                                                                                                                                 
        at org.jgroups.protocols.relay.RELAY2.handleRelayMessage(RELAY2.java:498)                                                                                                                                                            
        at org.jgroups.protocols.relay.Relayer$Bridge.receive(Relayer.java:200)                                                                                                                                                              
        at org.jgroups.JChannel.up(JChannel.java:819)                                                                                                                                                                                        
        at org.jgroups.stack.ProtocolStack.up(ProtocolStack.java:893)                                                                                                                                                                        
        at org.jgroups.protocols.FRAG3.up(FRAG3.java:171)                                                                                                                                                                                    
        at org.jgroups.protocols.FlowControl.up(FlowControl.java:351)                                                                                                                                                                        
        at org.jgroups.protocols.pbcast.GMS.up(GMS.java:864)                                                                                                                                                                                 
        at org.jgroups.protocols.pbcast.STABLE.up(STABLE.java:240)                                                                                                                                                                           
        at org.jgroups.protocols.UNICAST3.deliverMessage(UNICAST3.java:1002)                                                                                                                                                                 
        at org.jgroups.protocols.UNICAST3.handleDataReceived(UNICAST3.java:728)                                                                                                                                                              
        at org.jgroups.protocols.UNICAST3.up(UNICAST3.java:383)                                                                                                                                                                              
        at org.jgroups.protocols.pbcast.NAKACK2.up(NAKACK2.java:600)                                                                                                                                                                         
        at org.jgroups.protocols.VERIFY_SUSPECT.up(VERIFY_SUSPECT.java:119)                                                                                                                                                                  
        at org.jgroups.protocols.FD_ALL.up(FD_ALL.java:199)                                                                                                                                                                                  
        at org.jgroups.protocols.FD_SOCK.up(FD_SOCK.java:252)                                                                                                                                                                                
        at org.jgroups.protocols.MERGE3.up(MERGE3.java:276)                                                                                                                                                                                  
        at org.jgroups.protocols.Discovery.up(Discovery.java:267)                                                                                                                                                                            
        at org.jgroups.protocols.TP.passMessageUp(TP.java:1229)                                                                                                                                                                              
        at org.jgroups.util.SubmitToThreadPool$SingleMessageHandler.run(SubmitToThreadPool.java:87)                                                                                                                                          
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)                                                                                                                                                   
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)                                                                                                                                                   
        at java.lang.Thread.run(Thread.java:745)