I have currently an error on store sync after "authorized":
INFO: Ext.io.data.Proxy.sync: Start sync of database: xxx app.js:1
INFO: client-pubsub: 6IyQiJUA25wBIx6LxlVNGxFEd0xbLx subscribed to Users/CxwPSxOFxSrXoTx7xR3S2TcowZXt
WARNING: RPC request has timed out as there was no reply from the server. Correlation Id: 4 app.js:1
WARNING: See documentation for Ext.io.Io.setup (rpcTimeoutDuration, rpcTimeoutCheckInterval) to configure the timeout check app.js:1
ERROR: Error running RPC timeout checks -> TypeError
with TypeError.type = "non_object_property_load"

Is it a Sencha server problem ?