Same issue here… 
myopenhab doesn’t work for me since a month or so.
Version: 2.3.0-SNAPSHOT (#1204)
I’ve even created a new account and generated new UUID and Secret files.
Still nothing, so I’m assuming it’s the server issue.
cc: @digitaldan
==> /var/log/openhab2/openhab.log <==
2018-02-05 22:10:30.986 [ERROR] [io.openhabcloud.internal.CloudClient] - Socket.IO error: {}
io.socket.engineio.client.EngineIOException: xhr post error
at io.socket.engineio.client.Transport.onError(Transport.java:71) [267:org.openhab.io.openhabcloud:2.3.0.201802031138]
at io.socket.engineio.client.transports.PollingXHR.access$000(PollingXHR.java:19) [267:org.openhab.io.openhabcloud:2.3.0.201802031138]
at io.socket.engineio.client.transports.PollingXHR$4$1.run(PollingXHR.java:88) [267:org.openhab.io.openhabcloud:2.3.0.201802031138]
at io.socket.thread.EventThread$2.run(EventThread.java:80) [267:org.openhab.io.openhabcloud:2.3.0.201802031138]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:?]
at java.lang.Thread.run(Thread.java:748) [?:?]
Caused by: java.io.IOException: 400
at io.socket.engineio.client.transports.PollingXHR$Request$1.run(PollingXHR.java:218) ~[?:?]
... 1 more
2018-02-05 22:10:31.027 [INFO ] [io.openhabcloud.internal.CloudClient] - Disconnected from the openHAB Cloud service (UUID = XXXX, base URL = http://localhost:8080)
==> /var/log/openhab2/openhab.log <==
2018-02-05 22:11:55.296 [WARN ] [okhttp3.OkHttpClient ] - A connection to https://myopenhab.org/ was leaked. Did you forget to close a response body?
==> /var/log/openhab2/openhab.log <==
2018-02-05 22:11:57.388 [INFO ] [io.openhabcloud.internal.CloudClient] - Disconnected from the openHAB Cloud service (UUID = XXX, base URL = http://localhost:8080)
Thank you for your work!