It's possible you're using an access token which you have created for an evaluation environment when testing signNow's API. If this is not the case, then the token may have expired. There are 2 ways to create a new access token: - using password as 'grant_type' or using a refresh token, which is issued together with each new access token. Here's the example of a method to create access tokens with a username and password as 'grant_type'. And this is how you can create an access token by a refresh token.
Does Signnow's access token expire after a certain period of time and how to reset it without going through registration again?