Daily load operation attempts generate an "Invalid refresh token" error in Postman when attempting to perform a refresh using the same refresh token. Load attempts can also generate a 401 error with the Invalid access token, rather than an invalid refresh token error. Both errors prevent successful completion of a daily load.
The most likely the root cause for "Invalid Refresh Token" or "Invalid Access Token" error is that the requester is sending the same refresh and access tokens through different IP addresses. Requesters do not normally control this routing mechanism.
Use the Revoke API to revoke the refresh token before its 28-day expiration window closes.
Note: Access tokens last at least 450 seconds. If an access token lasts less than 450 seconds, then it will not use the refresh token to get a new access token and would instead generate expiration errors.