Visiting your site lajkiinsta.pl from FF yes the homepage reports broken SSL but I've see this many times in FF. If you visit another page ie contact and back to home it corrects in FF.
Chrome / Epic web browser first visit SSL no problem.
I would surmise that your site was http before so, I would suggest editing your htaccess file and forcing the domain to server https only.
If you not familiar with htaccess I strongly suggest you ask your hosting company to make the changes, one wrong character in that file and your site less.