Error codes below relate to authentication errors:

Error numberError messageAdditional info and instruction
5021Unable to communicate with the testing server. Please contact your administrator. 

Administrators should ensure that is designated as a trusted site.

5022Unable to communicate with the testing server. Please contact your administrator.  The testing server URL that was requested was not found (404) or there was an internal server error (500) during authentication.  
5023Unable to communicate with the testing server. Please contact your administrator.  
5024Unable to communicate with the testing server. Please contact your administrator.
5025There has been a problem loading this item. Please contact your administrator.
5026Invalid login token. Please try again.Logout and log back in. Autologin using an authentication token has failed because the token has expired or is otherwise invalid or not recognized. The authentication token is requested from TestNav by the customer site and must be used within five minutes to allow the examinee to access the test; extended inactivity or network connections can cause this.
5027TestNav is unable to write to the local drive due to browser security settings. Testing cannot continue. Contact your local system administrator. TestNav can't write necessary files to the local system. This is because the operating system is keeping the browser in a sort of quarantine (sandbox). Some operating systems do this to applications that can be used to cause system instability or other harm. 

Select a new location for student responses to be saved. If that does not work, view the student's responses and save or print a record of the files so that the responses can be reentered after you close TestNav and retake the test using a different machine.
5028Your registration does not include enough seal codes for this form.  Please contact your test administrator.The test administrator should check the number of seal codes.
5029TestNav has detected the Pinterest application, and will close your test session. Your administrator must disable the Pinterest Chrome extension and refresh the browser before resuming your test session. Testnav displays this error in the Chrome browser if the Pinit plugin is running in the background during a secure test. You must disable the Pinit plugin from Chrome extension and refresh the browser. Then, the student should log in again.