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Solution: The default value is 30 minutes before security validation times out. You can however turn it off through the Central admin console if you want to try it out just in case.
Central Administration à Application Managementà Web Application General settings.
Scroll down to Web Page Security Validation. You can extend the time out, or turn the timeout off. (Only do this for internal protected networks.)
Anandhan.S Remember to 'mark or propose as answer' or 'vote as helpful' as appropriate.