From bug 4840 comment #12 and #13: NoVNC doesn't seem to work when logging in to a system with ISO8859-1 usernames. ASCII usernames work fine, I haven't tested other username encodings. Here's what Firefox 28 has to say about this: recv_message, caught exception: Util.decodeUTF8@https://sunray.lkpg.cendio.se:300/include/util.js:237 RFB/init_msg@https://sunray.lkpg.cendio.se:300/include/rfb.js:923 RFB/handle_message@https://sunray.lkpg.cendio.se:300/include/rfb.js:542 recv_message@https://sunray.lkpg.cendio.se:300/include/websock.js:220 Here's what Chrome 34.0.1847.116 says: recv_message, caught exception: URIError: URI malformed at decodeURIComponent (native) at Object.Util.decodeUTF8 (https://sunray.lkpg.cendio.se:300/include/util.js:237:31) at RFB.init_msg (https://sunray.lkpg.cendio.se:300/include/rfb.js:923:24) at Object.RFB.handle_message [as message] (https://sunray.lkpg.cendio.se:300/include/rfb.js:542:9) at WebSocket.recv_message (https://sunray.lkpg.cendio.se:300/include/websock.js:220:27)
The usernames must match the server locale. We have decided to document this and improve the error message.