Error Message with IdP "LoginContext key cookie was not present in request"

[Patrick Rynhart]

Hi,

We have two Shibboleth IdPs (a production and test instance) which is 
federated with the same SP (Lynda.com).  Until recently, both have been 
functioning correctly.  However, within the last few days, our 
production IdP instance fails when attempting to log into this SP. 
After turning up the log level to DEBUG, the error message "LoginContext 
key cookie was not present in request" is found in the logs (just after 
the POST).  Other SPs that our Prod IdP is federated with aren't 
affected.  We've also tried different browser sessions and user 
combinations.

I provide DEBUG logs during a login attempt for both the Production (not 
working with Lynda.com) IdP and the Test (working with Lynda.com) IdPs. 
  The version of Shibboleth used in Prod is 2.3 while that in Test is 
2.4 - but they are configured similarly.  I am posting both versions for 
comparison because the bulk of the logs are similar and I can't spot any 
(obvious) differences as to one should fail while the other succeed.

Production IdP (idp.massey.ac.nz) - Not Working with Lynda.com:
http://www.massey.ac.nz/~prynhart/downloads/LyndaCom_Login_Error_20140104.txt

Test IdP (idp-test.massey.ac.nz) - Working With Lynda.com:
http://www.massey.ac.nz/~prynhart/downloads/LyndaCom_Login_Error_20140104_via_TestIdP.txt

If someone could please help me troubleshoot this issue it would be most 
appreciated.  The reason for the "break" isn't known - in particular 
there haven't been any (known) configuration changes at either end.

With Thanks,

Patrick

-- 
Patrick Rynhart
Systems Engineer
Infrastructure Support Section
Information Technology Services
Massey University
Palmerston North
New Zealand