Error codes below relate to program state and related network communication errors:

Error numberError messageAdditional info and instruction
6000 A system error has occurred. Please log in to your test again. 
6001 A system error has occurred. Please log in to your test again. 
6002A system error has occurred. Please log in to your test again. 
6021Unable to communicate with the testing server. Please contact your administrator. Contact your local system or network administrator; the network connection was either not found or lost during authentication. 

6022Unable 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.  

6023Unable to communicate with the testing server. Please contact your administrator. 

 There was a parser error when saving or retrieving state. 

6024Unable to communicate with the testing server. Please contact your administrator.

6025There has been a problem loading this item. Please contact your administrator.