Dynamics CRM - System.ArgumentNullException: Value cannot be null.Parameter name: g

Request.xml

<s:Envelope 
    xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
    <s:Header>
        <SdkClientVersion 
            xmlns="http://schemas.microsoft.com/xrm/2011/Contracts">
        </SdkClientVersion>
    </s:Header>
    <s:Body>
        <Execute 
            xmlns="http://schemas.microsoft.com/xrm/2011/Contracts/Services" 
            xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
            <request i:type="b:QualifyLeadRequest" 
                xmlns:a="http://schemas.microsoft.com/xrm/2011/Contracts" 
                xmlns:b="http://schemas.microsoft.com/crm/2011/Contracts">
                <a:Parameters 
                    xmlns:b="http://schemas.datacontract.org/2004/07/System.Collections.Generic">
                    <a:KeyValuePairOfstringanyType>
                        <b:key>LeadId</b:key>
                        <b:value i:type="a:EntityReference">
                            <a:Id>88e2e5ab-06b2-e611-80f0-c4346bc532a0</a:Id>
                            <a:LogicalName>lead</a:LogicalName>
                        </b:value>
                    </a:KeyValuePairOfstringanyType>
                    <a:KeyValuePairOfstringanyType>
                        <b:key>CreateAccount</b:key>
                        <b:value i:type="c:boolean" 
                            xmlns:c="http://www.w3.org/2001/XMLSchema">false
                        </b:value>
                    </a:KeyValuePairOfstringanyType>
                    <a:KeyValuePairOfstringanyType>
                        <b:key>CreateContact</b:key>
                        <b:value i:type="c:boolean" 
                            xmlns:c="http://www.w3.org/2001/XMLSchema">true
                        </b:value>
                    </a:KeyValuePairOfstringanyType>
                    <a:KeyValuePairOfstringanyType>
                        <b:key>CreateOpportunity</b:key>
                        <b:value i:type="c:boolean" 
                            xmlns:c="http://www.w3.org/2001/XMLSchema">true
                        </b:value>
                    </a:KeyValuePairOfstringanyType>
                    <a:KeyValuePairOfstringanyType>
                        <b:key>OpportunityCurrencyId</b:key>
                        <b:value i:type="a:EntityReference">
                            <a:Id>c585ecfb-a9e6-e511-80db-c4346bc4bef0</a:Id>
                            <a:LogicalName>lead</a:LogicalName>
                        </b:value>
                    </a:KeyValuePairOfstringanyType>
                    <a:KeyValuePairOfstringanyType>
                        <b:key>OpportunityCustomerId</b:key>
                        <b:value i:nil="true" />
                    </a:KeyValuePairOfstringanyType>
                    <a:KeyValuePairOfstringanyType>
                        <b:key>SourceCampaignId</b:key>
                        <b:value i:nil="true" />
                    </a:KeyValuePairOfstringanyType>
                    <a:KeyValuePairOfstringanyType>
                        <b:key>Status</b:key>
                        <b:value i:type="a:OptionSetValue">
                            <a:Value>433750008</a:Value>
                        </b:value>
                    </a:KeyValuePairOfstringanyType>
                    <a:KeyValuePairOfstringanyType>
                        <b:key>SuppressDuplicateDetection</b:key>
                        <b:value i:type="c:boolean" 
                            xmlns:c="http://www.w3.org/2001/XMLSchema">false
                        </b:value>
                    </a:KeyValuePairOfstringanyType>
                </a:Parameters>
                <a:RequestId i:nil="true" />
                <a:RequestName>QualifyLead</a:RequestName>
            </request>
        </Execute>
    </s:Body>
</s:Envelope>

Response.xml

<s:Envelope 
    xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
    <s:Body>
        <s:Fault>
            <faultcode>s:Client</faultcode>
            <faultstring 
                xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">An unexpected error occurred.
            </faultstring>
            <detail>
                <OrganizationServiceFault 
                    xmlns="http://schemas.microsoft.com/xrm/2011/Contracts" 
                    xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
                    <ErrorCode>-2147220970</ErrorCode>
                    <ErrorDetails 
                        xmlns:a="http://schemas.datacontract.org/2004/07/System.Collections.Generic" />
                    <Message>An unexpected error occurred.</Message>
                    <Timestamp>2016-11-28T06:23:28.5212009Z</Timestamp>
                    <ExceptionSource i:nil="true" />
                    <InnerFault>
                        <ErrorCode>-2147220970</ErrorCode>
                        <ErrorDetails 
                            xmlns:a="http://schemas.datacontract.org/2004/07/System.Collections.Generic" />
                        <Message>System.ArgumentNullException: Value cannot be null.Parameter name: g</Message>
                        <Timestamp>2016-11-28T06:23:28.5212009Z</Timestamp>
                        <ExceptionSource i:nil="true" />
                        <InnerFault i:nil="true" />
                        <OriginalException i:nil="true" />
                        <TraceText i:nil="true" />
                    </InnerFault>
                    <OriginalException i:nil="true" />
                    <TraceText i:nil="true" />
                </OrganizationServiceFault>
            </detail>
        </s:Fault>
    </s:Body>
</s:Envelope>