Error 502 Bad Gateaway nginx

When I created my account it worked totally perfect without any error after month at the end of year 2018 my web had sometimes this problem and few day ago it was usual. It was annoying and after deleting my searches it worked only for a day and I tried it few times delete my searches and it’s same. I restart my notebook many times and I tried all ways how to repair it and today (15.1.2019) it works only for my mobile (I can give you my system specifications of my devices if it is needed). Please admin, help me. Domain is from freenom.com. Web is http://serialyonline.ga/ (It’s in Czech language). I haven’t cloudfare, ssl or more domains.

Sorry, it worked after few hours