Symptoms
Appit cannot be reached on target environment error received when attempting to access any K2 components:
"One or more errors occurred"
Diagnoses
The security token has expired for the Appit instance.
Resolution
Running the registration wizard will refresh the token. This is found at Appit Admin console > Registration Wizard.
More information about the shelf life of security tokens can be found in the following kb article:
http://help.k2.com/onlinehelp/K2Appit/UserGuide/current/default.htm_Management_and_Administration/Admin_Token_Refresh.htm