Why is refresh_token_expires_in always 0?

[aledhi38]

I'm working on an OAUTH proxy but I always get this result in the response: "refresh_token_expires_in" : "0".

The code for generate access token policy is:

<Operation>GenerateAccessToken</Operation>

<ExpiresIn>3600000</ExpiresIn>

<RefreshTokenExpiresIn>86400000</RefreshTokenExpiresIn>

<SupportedGrantTypes>

<GrantType>client_credentials</GrantType>

</SupportedGrantTypes>

<GrantType>request.queryparam.grant_type</GrantType>

<GenerateResponse enabled="true"/>

I also have Refresh access token policy.

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

<OAuthV2 name="RefreshAccessToken">

<Operation>RefreshAccessToken</Operation>

<ExpiresIn>180000</ExpiresIn>

<GrantType>request.queryparam.grant_type</GrantType>

<GenerateResponse/>

</OAuthV2>

I have tried different ways based on Apigee Doc but no luck. Can someone help me with any ideas?