I have set up account linking for my skill and everything goes well. Log in, log out, get access_token.
But sometimes, after a long time standby(e.g one day), the session will not contain access_token though my skill is still remain log in. I have to disable my skill and enable it to log in again. Since I re-link account, it works fine. The session will contain access_token.
Why it happens or are there any set up for skill to keep session send access_token back to me anytime even already standby for long time?