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asp.netiisforms-authenticationload-balancing

ASP.NET Form Authentication in balanced environment

Getting 401 errors when trying to use ASP.NET back end in load balanced environment (2 web servers). Windows log says:

Event code: 4005 
Event message: Forms authentication failed for the request. Reason: The ticket supplied was invalid. 
Event time: 6/6/2012 10:34:27 AM 
Event time (UTC): 6/6/2012 5:34:27 PM 
Event ID: de68a535d53e4bdfb11ace24a97c63c9 
Event sequence: 18 
Event occurrence: 7 
Event detail code: 50201

Machine key on both IIS applications configured to be same. What else can cause this problem?

Solution

  • As it turned out two web servers had slightly different set of windows patches installed. As soon as we installed all same patches on both of them - problem was solved.