kii cloud json error

Hi,
I'm using kii cloud; when I register as a user in unity, it gives me this error.

Register failed : KiiCorp.Cloud.Storage.IllegalKiiBaseObjectFormatException: Value <!doctype of type System.String cannot be converted to JSONObject
UnityEngine.Debug:Log(Object)
KiiCloudLogin:<register>m__5(KiiUser, Exception) (at Assets/Script/KiiCloud/KiiCloudLogin.cs:104)
KiiCorp.Cloud.Storage.<Register>c__AnonStoreyF:<>m__1C(KiiUser, Exception)...

kii cloud json error