Access code life time

I am creating access token to login and send the agreement to some one using access_code in my JAVA application.

After some time the code are not working and give the following error

com.adobe.sign.utils.ApiException: invalid authorization code

    at com.adobe.sign.utils.ApiClient.throwApiException(ApiClient.java:679)

    at com.adobe.sign.utils.ApiClient.invokeAPI(ApiClient.java:645)

    at com.adobe.sign.api.OAuthApi.getAccessToken(OAuthApi.java:108)

    at com.adobe.sign.utils.ApiUtils.getHeaderParams(ApiUtils.java:103)

Is the access code was invalidate after some time or it will stay alive for life long.