ASP.Net MVC + Facebook oAuth + rewrite rule cause response_type=code

I'm experimenting an issue when I create some rewrite rule into my ASP.Net app.

When I activate this rule :

<rewrite>
  <rules>
    <rule name="Main Rule" stopProcessing="true">
      <match url="^.*" />
      <conditions logicalGrouping="MatchAll">
        <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
        <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />
        <add input="{REQUEST_URI}" matchType="Pattern" pattern="^/api/" negate="true" />
        <add input="{REQUEST_URI}" matchType="Pattern" pattern="^/token" negate="true" />
      </conditions>
      <action type="Rewrite" url="/" />
    </rule>
  </rules>
</rewrite>

My application will try to authenticate through Facebook with response type : code instead of token.

When I disable It, I'm well redirecting with response_type = token

Is there anybody who had to deal with it ? thank you.