Hi liron,
It sounds like you’ve already taken a look at the preview button post and adjusted your proxy settings, but still see that clicking “Preview” doesn’t show your prototype in the browser.
To confirm, are you able to generate local HTML via “Publish > Generate HTML” without issues?
When you click the preview button, does it fail to preview in all browsers, or just one? Do you get any errors printed in the browser, or is the screen just blank?
Are there any errors in the browser if you right-click on the page, choose “Inspect”, and then click the “Console” tab in the window that opens?
To verify, does this issue happen with all files, or just one? If the issue seems to be file specific, then would you mind sending a copy of the file so that we can take a look? If the file is confidential or if this issue is urgent, then please email support@axure.com so that we can assist you one on one. Thanks!