The reported error is:
10-29 11:08:50.655 20895-21155/I/System.out: (ERROR): io.ably.lib.transport.WebSocketTransport: Unexpected exception processing received binary message
10-29 11:08:50.657 20895-21155/I/System.out: io.ably.lib.types.AblyException: java.lang.ClassCastException: java.lang.String cannot be cast to byte[]
The likely problem is that a message is being received with an encoding ending in utf-8, which implies that the data field is a byte[], but the error message tells us it in fact is a String. Strictly, that's a malformed message, but the library should handle it gracefully by returning the unchanged data.