I have a trouble between integration with SalesForce and our's service.
We are using oauth2 authorization and SalesForce REST API.
Our clients authorize successfully for the first time and get the access and refresh tokens. But the access token is expired. So the error is always 'Session expired or invalid'.
When we try to refresh it via refresh token request it returns the same access token. And so the error is the same.
Refresh token has unlimited lifetime in the salesforce app settings.
Are we doing something wrong? or our clients has some bad settings?