I am using a 3rd party application to transfer client information from one system to a web portal. Once I transfer the information, I click a button in the 3rd party application which opens a link to a clients file. At this stage, FireFox is supposed to prompt me to select an SSL Certificate. It was doing so until around mid June 2017. I have added the site to the trusted sites within the Internet Options in the control panel in my pc and have even tried setting the SSL Certificate to use 'Client Authentication'. I have tried many other things to resolve this problem, however, including the Certificate chain and trust relationships. the problem still exists. The SSL Certificate is installed in FireFox. I have also encountered the same problem with Google Chrome and Internet Explorer around the same time. As soon as I set the Certificate to use 'Client Authentication', Internet Explorer worked, however, Google Chrome and Mozilla FireFox did not. I would have expected Google Chrome to work once Internet Explorer started working as they use the same Certificate Store. This problem has occurred on a small work network not using a proxy, I have ensured the 3rd party application I use, plus the system I am taking the data from and all 3 browsers have exceptions within the Firewall being Kaspersky Internet Security. I cannot see what the problem is. As the two browsers being Google Chrome and Mozilla FireFox are no longer prompting for the SSL Certificate, I now get an error message saying 'Client certificate must be present'. It's almost as if the browsers are hitting cancel and not allowing the dialogue box to appear to let me select an SSL Certificate. Has anyone experienced this before and if so, do you know how to fix this? Thanks.