refresh token for other users

[JimmyL]

Im trying to refresh token for another user of my app. Before i get intraday heart rate data.

But i get this response..

 {StatusCode: 400, ReasonPhrase: 'Bad Request', Version: 1.1, Content: System.Net.Http.StreamContent, Headers:
{
Transfer-Encoding: chunked
Connection: keep-alive
Vary: Accept-Encoding
X-Frame-Options: SAMEORIGIN
CF-RAY: 2fdfeb9b18b73d5b-CPH
Cache-Control: no-cache, private
Date: Mon, 07 Nov 2016 09:57:19 GMT
Server: cloudflare-nginx
Content-Language: en-DK
Content-Type: application/json; charset=utf-8

If i don't refresh the token it works fine.. The problem is i wanna get my users data during the night, but at that point their tokens is expired..
Can i as app owner even refresh their tokens?

[JimmyL]

Found this error also 

{"errors":[{"errorType":"invalid_grant","message":"Refresh token invalid: 35a96be491c7fd04b5e9f513265b9319e5698125ce7f7666bf880dd0f728cbdc. Visit https://dev.fitbit.com/docs/oauth2 for more information on the Fitbit Web API authorization process."}],"success":false}

But it isen't in docs

[AndrewFitbit]

---

@JimmyL wrote:

Found this error also 

{"errors":[{"errorType":"invalid_grant","message":"Refresh token invalid: 35a96be491c7fd04b5e9f513265b9319e5698125ce7f7666bf880dd0f728cbdc. Visit https://dev.fitbit.com/docs/oauth2 for more information on the Fitbit Web API authorization process."}],"success":false}

---

@JimmyL The error means you're attempting to use a refresh token that's been invalidated. There's a related thread about refresh tokens that might help.