We have an odd problem with an intranet. If a user views a PDF they get logged off. They all use Firefox PDF viewer. Apache 2.4.18 Ubuntu 16.04.3 LTS, Firefox 57.0.3 32 bit on Windows 7.
Authentication with mod_auth_form, session is stored with a cookie and encrypted with mod_session_crypto.
When the user views the PDF the server logs AH00011:ap_cookie: client submitted cookie session more than once.
I’ve watched the developer tools and the server doesn’t set a session cookie on this request.
If we change the cookie so it is not encrypted then it works fine.
Please can anyone help us with the Apache configuration?