Why can't students log in take their tests?

If a student cannot login to take a test then the following items should be checked:

Teacher or School Admin Tasks

Ensure the status of the sitting is displayed as Live or Started in the Sittings List. See View the Sittings List.
Check the status of the student to ensure that another student has not used the same access code. See Monitor Student Progress.
Check the student's activities within Testwise. See View Student Activity Log.

Ensure the student has been given the correct access code.
Ensure the student has a copy of the Test Taking Instructions for Students and has followed all the steps correctly.
Ensure the student has entered the correct web address and typed the access code in correctly. Email both of them to student to ensure that there are no typing errors or type them into their computer yourself. The web address for accessing the Test Lobby is https://www.testingforschools.com/code.