Exception: Parameter [nickName] value is invalid

I'm keep getting this error. I tried all possible values.

Exception: Parameter [nickName] value is invalid  SDK HTTP Error at https://platform.devtest.ringcentral.com/restapi/v1.0/account/~/extension/~/address-book/contact/  Response text: {    "errorCode" : "InvalidParameter",    "message" : "Parameter [nickName] value is invalid",    "errors" : [ {      "errorCode" : "CMN-101",      "message" : "Parameter [nickName] value is invalid",      "parameterName" : "nickName"    } ],    "parameterName" : "nickName"  }