It seems the refresh token is getting expired immediately after using once, and the api to refresh access token must be called atleast 8 seconds after on refresh or else it would return the invalid token error
This is the error im receving
{
"error": "invalid_grant",
"error_description": "This refresh token is invalid"
}
Running into same issue. Refresh Token is expiring after 1 use. Everything worked fine up until last week or so. Refresh Token should be good up to 1 year per their documentation.