Cognos service fails to restart: CFG-ERR-0106

[lewisk]

I have an installation of Cognos BI 10.2.1 (Windows 64 bit) which was recently upgraded with Fix Pack 6.  I had already restarted the Cognos service after installing this Fix Pack and everything seemed fine.

Today I was notified that no users could open Report Studio.  Attempting myself, I got the message CAF-WRN-2082.  I looked in pkiauth_6-3-2015.log and found this:

(19:14:24)pkiauth.logon   theAuthRequest: com.ibm.cognos.camaaa.internal.common.IBiBusHeaderCompatibilityAdapter2@c2120665
(19:14:24)REMOTE_USER header did not contain an EDIPI.  Aborting logon.
(19:14:24)Contents of header:
(19:14:24)Exception details: null

Not having any idea what the problem might be, I decided to try restarting the service, which often resolves mysterious errors.  I opened IBM Cognos Configuration and clicked the Restart button.  It stopped for a long while having displayed "camAsyncService, StartService, Success".  During this time I saw that the pkiauth file was growing rapidly.  It finally gave up with the message: "CFG-ERR-0106 IBM Cognos Configuration did not receive a response from the IBM Cognos service in the time allotted."

Looking in the pkiauth file I see numerous instances of this:

(19:42:53)pkiauth.logon   theAuthRequest: com.ibm.cognos.camaaa.internal.common.IBiBusHeaderCompatibilityAdapter2@84c403a4
(19:42:53)REMOTE_USER header did not contain an EDIPI.  Aborting logon.
(19:42:53)Contents of header:
(19:42:53)Exception details: String index out of range: -10

At this point I have no idea what could be wrong.  I have not made any configuration changes since installing the last Fix Pack.  I would appreciate any suggestions.

[cognos810]

Is it a single server install ? Was the fix pack applied across the board, in case of a distributed install?