Zwave extender makes problems

Hi all

to improve Zwave network quality I added an extender (Aeotec DSD37-ZWEU) into my running OH1 environment:

IMO the device is working but according to my logfile there are various errors. Can anyone please explain what is going wrong and how I can resolve this issue?

The following errors are repeated again and again.

Thanks & best regards
John

2017-04-08 08:29:46.451 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Got an error while sending data. Resending message.
2017-04-08 08:29:50.565 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Got an error while sending data. Resending message.
2017-04-08 08:35:46.473 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Got an error while sending data. Resending message.
2017-04-08 08:37:16.450 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Got an error while sending data. Resending message.
2017-04-08 08:37:20.564 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Got an error while sending data. Resending message.
2017-04-08 08:37:24.722 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Node is DEAD. Dropping message.
2017-04-08 08:37:24.725 [WARN ] [i.p.s.IsFailedNodeMessageClass] - NODE 8: Is currently marked as failed by the controller!
2017-04-08 08:37:24.727 [WARN ] [i.p.s.IsFailedNodeMessageClass] - NODE 8: Is currently marked as failed by the controller!
2017-04-08 08:37:31.356 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Node is DEAD. Dropping message.
2017-04-08 08:37:31.446 [ERROR] [signSucReturnRouteMessageClass] - NODE 8: Assign SUC return routes failed with error 0x1.
2017-04-08 08:37:31.597 [ERROR] [signSucReturnRouteMessageClass] - NODE 8: Assign SUC return routes failed with error 0x1.
2017-04-08 08:37:31.747 [ERROR] [signSucReturnRouteMessageClass] - NODE 8: Assign SUC return routes failed with error 0x1.
2017-04-08 08:41:01.446 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Got an error while sending data. Resending message.
2017-04-08 08:42:31.557 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Got an error while sending data. Resending message.
2017-04-08 08:42:35.655 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Got an error while sending data. Resending message.
2017-04-08 08:44:01.471 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Got an error while sending data. Resending message.
2017-04-08 08:45:31.505 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Got an error while sending data. Resending message.
2017-04-08 08:45:35.649 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Got an error while sending data. Resending message.
2017-04-08 08:45:39.792 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Node is DEAD. Dropping message.
2017-04-08 08:45:39.794 [WARN ] [i.p.s.IsFailedNodeMessageClass] - NODE 8: Is currently marked as failed by the controller!
2017-04-08 08:45:39.795 [WARN ] [i.p.s.IsFailedNodeMessageClass] - NODE 8: Is currently marked as failed by the controller!
2017-04-08 08:45:46.385 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Node is DEAD. Dropping message.
2017-04-08 08:45:46.491 [ERROR] [signSucReturnRouteMessageClass] - NODE 8: Assign SUC return routes failed with error 0x1.
2017-04-08 08:45:46.610 [ERROR] [signSucReturnRouteMessageClass] - NODE 8: Assign SUC return routes failed with error 0x1.
2017-04-08 08:45:46.776 [ERROR] [signSucReturnRouteMessageClass] - NODE 8: Assign SUC return routes failed with error 0x1.
2017-04-08 08:45:46.910 [ERROR] [signSucReturnRouteMessageClass] - NODE 8: Assign SUC return routes failed with error 0x1.
2017-04-08 08:47:41.360 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Node is DEAD. Dropping message.
2017-04-08 08:49:11.409 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Node is DEAD. Dropping message.
2017-04-08 08:50:41.446 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Node is DEAD. Dropping message.
2017-04-08 08:52:11.388 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Node is DEAD. Dropping message.
2017-04-08 08:53:41.424 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Node is DEAD. Dropping message.
2017-04-08 08:55:11.398 [ERROR] [b.z.i.p.s.SendDataMessageClass] - NODE 8: Node is DEAD. Dropping message.