Problem:

The access token has expired.

Cause:

When you set up access tokens, you select a Start Date & Time. If you do not start the exam during the time the token is valid the token will expire. You will be unable to see the exams in the ACCA Secure Network Administrator, and the students will not be able to start the exam.

Solution:

There is no way to extend the access tokens yourself.  If the tokens were generated incorrectly ACCA are unable to amend the token times or issue you with a credit.  You will have to generate new tokens.