RefreshToken Expire with in 5 mintues

Sir,

Would you help me how to access Refresh token for 60 days, in my scenario refresh token expire for 2 time request.

https://api.box.com/oauth2/token

grant_type refresh_token

client_id ****************************

client_secret ****************************

refresh_token ****************************

O/P:

{
"access_token": "mmFnjw4lbZZZ8EvCQeq7GJzQmGqzbxes",
"expires_in": 4196,
"restricted_to": [],
"refresh_token": "Lnd6WybwKuKdAhqE3yYBI8fgPAgHgJ8ahRvXvG7NZ61uS3cibetwu9FPrKfJH5Tn",
"token_type": "bearer"
}

for 2 time request with below 5 mint, i used same url again 

{
"error": "invalid_grant",
"error_description": "Refresh token has expired"
}

above message displayed,

so what can i do for above error message