Hi there, We have a weird problem with firefox only (not this problem with other web browser like Chrome, Ie or Edge). The problem is that we cannot browse this website at the same time. No problem to browse one website, but going on the seconde one and you will get on 404 error. Not Found ________________________________________ HTTP Error 404. The requested resource is not found. Same error for 3 others. Just waiting few minutes (at least 5min), refresh the second website, it’s working coming back on the first tab (with the first website), refresh and you get the error 404. This problem occurs only when we are using IPV6 connexion on an HTTPS websites (only on some of ours web sites (https://www.ticpharma.com/home.php, https://www.techopital.com/ https://www.gerontonews.com, https://www.ticsante.com/home.php and https://www.apminternational.fr/). These 5 website sharing the same SSL certificats. It’s a multi domain SSL certificats provide by Gandi.net. No problem when we use the Firefox PRIVATE windows. No problem when we browse theses websites in http and IPV6. No problem when we browse theses websites in httpS and IPV4. No problem with other browser in httpS and IPV6. So only problem with Firefox, in IPV6 and HPPS. This problem occurs on multiple computers, with diffrent Anti-Virus, from different location, for different network and ISP provider. So I guess there is a bug somewhere in firefox. Thanks for your help. Regards.