not able to access xsd in a wsdl

In a wsdl file, i try to use some element

My PolicyRequest.xsd file

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:p="http://ift.tt/YhNS0L"
xmlns:n="http://ift.tt/1rFO8z1"
xmlns:c="http://ift.tt/YhNQGk"
xmlns:xsd="http://ift.tt/tphNwY"
elementFormDefault="qualified">

<xsd:import namespace="http://ift.tt/YhNS0L"
    schemaLocation="Payment.xsd" />

<xsd:import namespace="http://ift.tt/1rFO8z1"
    schemaLocation="Note.xsd" />

<xsd:element name="PolicyRequest">
    <xsd:complexType>
        <xsd:sequence>
            <xsd:element name="Payments" type="p:Payment"
                maxOccurs="unbounded" minOccurs="1" />
            <xsd:element name="Notes" type="n:Note" maxOccurs="unbounded"
                minOccurs="1" />
        </xsd:sequence>
    </xsd:complexType>
</xsd:element>

My wsdl file

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<wsdl:definitions xmlns:pr="http://ift.tt/1rFOaaj"
xmlns:prst="http://ift.tt/YhNS0P"
xmlns:soap="http://ift.tt/KIQHA2"
xmlns:tns="http://www.example.org/" xmlns:wsdl="http://ift.tt/LcBaVt"
xmlns:xsd="http://ift.tt/tphNwY" name="TNI"
targetNamespace="http://www.example.org/">
<wsdl:types>

    <xsd:schema xmlns:pr="http://ift.tt/1rFOaaj"
        targetNamespace="http://www.example.org/">

        <xsd:import namespace="http://ift.tt/1rFOaaj" schemaLocation="PolicyRequest.xsd" />

        <xsd:import namespace="http://ift.tt/YhNS0P" schemaLocation="PolicyResult.xsd" /> 

        <xsd:element name="PolicyRequest" type="pr:PolicyRequest"></xsd:element>
        <xsd:element name="PolicyResult" type="prst:PolicyResult"></xsd:element>

    </xsd:schema>

</wsdl:types>
<wsdl:message name="PolicyRequest">
    <wsdl:part element="pr:PolicyRequest" name="parameters" />
</wsdl:message>
<wsdl:message name="PolicyResult">
    <wsdl:part element="prst:PolicyResult" name="parameters" />
</wsdl:message>
<wsdl:message name="OfferRequest">
    <wsdl:part element="or:OfferRequest" name="parameters" />
</wsdl:message>

<wsdl:portType name="TNI">
    <wsdl:operation name="Purchase">
        <wsdl:input message="tns:NewMessage" />
        <wsdl:output message="prst:PolicyResult" />
        <wsdl:fault name="fault" message="tns:PurchaseFault"></wsdl:fault>
    </wsdl:operation>

</wsdl:portType>
<wsdl:binding name="TNISOAP" type="tns:TNI">
    <soap:binding style="document"
        transport="http://ift.tt/LcBaVu" />
    <wsdl:operation name="Purchase">
        <soap:operation soapAction="http://ift.tt/1rFO8Pu" />
        <wsdl:input>
            <soap:body use="literal" />
        </wsdl:input>
        <wsdl:output>
            <soap:body use="literal" />
        </wsdl:output>
    </wsdl:operation>

</wsdl:binding>
<wsdl:service name="TNI">
    <wsdl:port binding="tns:TNISOAP" name="TNISOAP">
        <soap:address location="http://www.example.org/" />
    </wsdl:port>
</wsdl:service>

In the wsdl file i get

XSD: Type reference 'http://ift.tt/1rFOaan' is unresolved

Why I'm not able to access element from my xsd?