Cognos may require its services to be restarted. This is seldom done. Typically a restart will clear up some of the known errors, including a "Gateway Error" received by users. Below steps must be done with notification to entire programming team before these steps are followed.  The reboot MUST be done in this order. 

RESOLUTION

STEP 1: RDP into ''cognos-db' and reboot.

STEP 2: RDP into 'cognos-app2' and reboot (wait 5 minutes as cognos-app2 comes up slowly).

STEP 3: RDP into 'cognos-app1' and reboot