It is scripted to post the form, as you can see in the attached screenshots. But the posts are sent to different addresses in Chrome and Firefox. Google Chrome posts to https://www.plm.automation.siemens.com/online/Shop?sku=SE788 Firefox posts to https://www.plm.automation.siemens.com/plmapp/se/en_US/online/Shop Probably the "on submit" script that constructs the correct address is not running (or not running correctly) in Firefox 56+ but when I look at the error console, nothing jumps out at me at the reason for the problem. The site's developer might be able to spot it quickly in a debugger if you notify them.