You may modify your app.config as shown in the following example:
<bindings>
<basicHttpBinding>
<binding name="Integration">
<security mode="Transport">
<transport clientCredentialType="None" proxyCredentialType="None" realm=""/>
<message clientCredentialType="Certificate" algorithmSuite="Default" />
</security>
</binding>
</basicHttpBinding>
</bindings>
Try adding message credentials on your app.config like:
<!-- language: xml -->
<bindings>
<basicHttpBinding>
<binding name="defaultBasicHttpBinding">
<security mode="Transport">
<transport clientCredentialType="None" proxyCredentialType="None" realm=""/>
<message clientCredentialType="Certificate" algorithmSuite="Default" />
</security>
</binding>
</basicHttpBinding>
</bindings>