小程序SDK异常

调用登录接口就出现这个问题，请问怎么解决啊！
Uncaught SyntaxError: Unexpected token u in JSON at position 0
at JSON.parse ()
at h._initConversation (jmessage-wxapplet-sdk-1.4.2.min.js:1)
at i.hook (jmessage-wxapplet-sdk-1.4.2.min.js:1)
at r.onReceive (jmessage-wxapplet-sdk-1.4.2.min.js:1)
at o. (jmessage-wxapplet-sdk-1.4.2.min.js:1)
at o.emit (jmessage-wxapplet-sdk-1.4.2.min.js:1)
at o.client.onevent (jmessage-wxapplet-sdk-1.4.2.min.js:1)
at o.onpacket (jmessage-wxapplet-sdk-1.4.2.min.js:1)
at o. (jmessage-wxapplet-sdk-1.4.2.min.js:1)
at o.emit (jmessage-wxapplet-sdk-1.4.2.min.js:1)