Cause, there are a number of possibilities caused, it could be because you are using a third-party application. Examples include follower enhancers.
"Expired Token. Please request a new password reset link."
Because when you use a third-party app, they need access permissions to your account that of course use Tokens, and each Instagram account has a different Token.
Instagram Access Token is a collection of characters combining between letters and numbers on an account, each account is of course different and consists of at least 30 characters.
Error or Expired Token on an IG account the root of the problem is the result of a changed application structure, either deleted or replace usability, and ironically when the user has not revoked access permissions in Manage Applications.
There are two ways to fix expired tokens on Instagram accounts.
The first way, you can request a request reset password reset link from Instagram via email. Our advice is just by email just to make it easier.
After getting the link from Instagram to reset the password, immediately do it and click.
If you forgot your email nor can't login to the mail of your Instagram account, please forget about the account and create a new account.
Or alternative way, find the third-party apps that you use, if necessary contact the developer, log back in through the app as in the previous or the first time you use it.
With that way, your token will recover, because all it needs is access permissions from third-party apps that may be undergoing structural changes.