@Sebastian_Switek Although the form doesn’t look like it’s sent, did the form submission appear in the Site Dashboard > Forms? Are there any errors in the console tab (second tab) that you can screenshot for us?
@Sebastian_Switek A 304 response just means the page hasn’t changed since the last time the browser asked for it, so it seems to be a caching thing. See if you can flush your cache or disable it in the debugger you’ve got open.
I find the bug. When site uses domain …assecobs.pl (intranet settings) IE set default emulation to IE 7 when it goes with webflow domain emulation is set to IE 11. Guys @campmdabt@samliew thx for your time and effort!