For example I have refresh token #1. When I make request:
POST https://oauth.accounting.sage.com/token
Content-Type: application/x-www-form-urlencoded
Accept: application/json
client_id=xxxxxxx
&client_secret=xxxxxxxxxx
&grant_type=refresh_token
&refresh_token=refresh_token_#1
I get response with new access and refresh token. But when I make request for renewing an Access Token again, I get:
"error": "invalid_grant",
"error_description": "the submitted refresh_token is invalid"
I need to change refresh token after 5 minutes too. It's very strange behavior.