Sounds like you need to ask the third party. Nothing much has changed in the ZP100 for many years.

I think the problem is to be related to the ZP100. Because all my other ZP100’s, I can go to the diagnostic webpage on http://:1400/xml/device_description.xml. Only with this zone player I get the message ERR_CONNECTION_REFUSED.

Hello Controlav,

thank you for the tip

the strange thing is that I can access the webpage http://:1400/xml/device_description.xml of all my ZP’s but not the one that gives troubles. On that one I get ERR_CONNECTION_REFUSED. 

For me, it looks like the problem is situated in that one Zoneplayer. I tried to reboot it already ;)

If http://:1400/xml/device_description.xml also fails after rebooting it then it seems like it is dead. May it RIP, it has given excellent service.

Thank for the input. I was indeed also afraid that it would be dead. The address http://<ipaddress>:1400/xml/device_description.xml fails also.

The strange thing is that the device is still playing music like it should and is perfectly showing up and being controllable from the Sonos S1 app.

This would imply that some devices can read data from the player, and some cannot, which indicates router troubles. Start by rebooting it. (Assuming your ip address is accurate, verify that listed in the S1 app vs the one you are trying).